First there were vinyl record players or more popularly known as the gramophones, then came cassette players and then compact disc players or CD players. A few other devices, such as the MiniDisc players, never really caught on. But a MP3 is different from all this. Whether you want to groove while working or entertain yourself while on your way back home, a portable MP3 player could suit all your musical needs. MP3 players storing thousands of songs supplant the traditional walkman style cassette and CD players. But the dearth of names in the space often confuses buyers, but worry not as Buy-o-logy helps you on your way to getting best in the market.
Storage
MP3 players come in two basic varieties. There are hard-disk based and flash memory-based players. Hard disk players tend to be larger on size and are more susceptible to damage due to the fragile nature of parts within. But on a positive side they have a better storage capacity, from 256MB to 60GB depending on the hard drive technology. On the other hand, flash-based players come with a limited storage, which may later be extended by using external storage cards. In effect, they do not suffer the limitations that owners of hard drive-based players face, such as fears of dropping their player or fragmentation. Such players are commonly integrated into USB keydrives. Generally, about 5,000 songs fit into a 20GB MP3 player.
Types of playable files
This is one of the most important things to keep in mind when buying a MP3 player. Most MP3 players play most audio types. The Apple iPod, for instance, is compatible with AAC, WAV, AIFF alongwith playing the usual MP3 songs. Meanwhile, Sandisk’s Sansa series supports WAV, WMA apart from MP3. The series also comes with a FM radio player. Microsoft’s Zune is expected to support WAV, WMA, AAC along with MP3.
The video option
Recent times have seen a slew of video-enabled players. The iPod supports MPEG-4 format but not the AVI. Major video downloads come in the AVI format. It would be advisable that you check the number of formats that your player supports. It would be useful that the player has a large display and provides for a video output to play stored movies on TV. And if you want to view video or photos on the device, the quality of the screen is an even more critical consideration.
The market and the price
The iPod continues to be a favourite among Indian users in this category. There are other players available like the Sandisk Sansa, Creative and Samsung also have their series of MP3 players. Then there is Sony’s Walkman series and Transcend too. The iPod nano can cost you Rs 7,000-8,000 depending on the storage size. While its video-enabled range can cost over Rs 15,000. Meanwhile, iRiver’s ranges between Rs 2,000 to Rs 15,000.
Creative’s MP3 range is priced between Rs 3,000-27,000 while Samsung’s range starts from Rs 5,000 going up to Rs 15,00. Sony’s flash-based players ranges between Rs 5,900 and Rs 16,000 while it has 6GB MP3 player at Rs 9,900 and 20GB HDD MP3 for Rs 20,000.
Use and user interface:
Your decision also depends on how you are going to use the device. For instance, joggers or frequent users will want a lightweight, flash-memory-based device, since hard drives don’t react well to the shock; audio aficionados who want lots of music at their fingertips should keep their eyes on the highest-capacity hard-drive models. Also, pay attention to the user interface. There is no use buying a player where you cannot locate your favourite songs or artists easily.
Power options
Mind your power options always. While some flash-based portable players use replaceable alkaline batteries, others alongwith most hard drive-based units feature a built-in rechargeable battery that cannot be removed. While these devices can keep going for tens of hours, if you’re not somewhere near a power outlet or a computer with a USB port, you might find yourself out of juice.
Where to buy music
If you decide you want to buy songs online, then you need to decide what music store you want to use. This can very much dictate what player you get because these tracks are sold with Digital Rights Management, which limits what you can do with the song. For iPod, iTunes stores is a good place to buy songs, while there are also other outlets like the MusicMatch online store or the Microsoft’s MusicLibrary. There is one catch here — none of these sellers have Hindi or regional songs. For that, you will have to hunt down websites like coolgoose.com or access P2P softwares like Kazaa or Limewire.
Word of Caution though - downloading from such sites is illegal. So what’s the next best thing to do... buy a MP3 CD and rip its content to your player.
http://infotech.indiatimes.com/Personal_Tech/Digital_Home/How_to_buy_an_MP3_player/articleshow/msid-1751355,curpg-1.cms
Thursday, May 31, 2007
Saving that disk!
What do you do when you pop an old CD or a DVD into the player and stare at fancy messages that essentially let you know your disc is bloody scratched?
Most people I know stare longingly at it for a while and then throw it away. I usually pull the offending disc out and use it as a coaster. But there are some blokes, like I discovered today, who will do anything to get it back to work. This is the story of one such bloke. Exasperated with damaged discs, he did some reading on how the thing is built. He finally figured that discs can be repaired if the scratches inflicted on its surface are filled with some substance. What it was, he wouldn’t know until he played around with a few options. To make things a little more difficult for himself, he set himself two conditions.
One, whatever method he hit upon, it ought to be executable in five minutes. Two, whatever it is that he eventually used, it ought to be commonly found at anybody’s home. Armed with these variables, he started experimenting.
The first thing he did was to burn music on five discs and scratch them with a scissor. Having done that, he took the first disc, poured water over it, and rubbed the disc gently with a piece of lint-free cloth to make sure the water embedded itself into the scratches. Didn’t work!
On the next attempt, he took a bottle of deodorant and sprayed it over the disc. The idea was simple. Deo contains isopropyl myristate dissolved in alcohol.
He was hoping that when the alcohol evaporated, the isopropyl myristate would find itself into the cracks. A cursory look at the disc two minutes later indicated it may work. It didn’t, again!
He looked around a bit and stumbled on lem-oil. This is something musicians use to protect wood surfaces on their instruments. It preserves the wood and tones down scratches and blemishes. After spraying the oil on the CD, he rubbed it vigorously with the lint-free cloth. Apparently, when he popped the CD into the player, it worked.
But the music didn’t sound right. In any case, lem-oil isn’t volatile enough to evaporate in five minutes. He dropped the idea and picked up toothpaste.
Now, the toothpaste method is something quite a few people have tried. It is a mild abrasive. So you take the tiniest bit of paste on the tip of your finger.
Without touching the CD itself with the finger, apply the toothpaste only around the scratched parts. Now put the CD under a thin stream of running water and tilt the CD. This way, the excess paste runs off and what remains gets into the CD. Apparently, his player spat the CD out.
A few other things later, he finally hit upon hair gel. Applied in much the same way toothpaste is, he followed up by rubbing it in and ran a thin stream of water on to loosen it up. This way, the excess gel was washed off. And the disc worked—perfectly.
http://infotech.indiatimes.com/Personal_Tech/Digital_Home/Saving_that_disk/articleshow/1979759.cms
Most people I know stare longingly at it for a while and then throw it away. I usually pull the offending disc out and use it as a coaster. But there are some blokes, like I discovered today, who will do anything to get it back to work. This is the story of one such bloke. Exasperated with damaged discs, he did some reading on how the thing is built. He finally figured that discs can be repaired if the scratches inflicted on its surface are filled with some substance. What it was, he wouldn’t know until he played around with a few options. To make things a little more difficult for himself, he set himself two conditions.
One, whatever method he hit upon, it ought to be executable in five minutes. Two, whatever it is that he eventually used, it ought to be commonly found at anybody’s home. Armed with these variables, he started experimenting.
The first thing he did was to burn music on five discs and scratch them with a scissor. Having done that, he took the first disc, poured water over it, and rubbed the disc gently with a piece of lint-free cloth to make sure the water embedded itself into the scratches. Didn’t work!
On the next attempt, he took a bottle of deodorant and sprayed it over the disc. The idea was simple. Deo contains isopropyl myristate dissolved in alcohol.
He was hoping that when the alcohol evaporated, the isopropyl myristate would find itself into the cracks. A cursory look at the disc two minutes later indicated it may work. It didn’t, again!
He looked around a bit and stumbled on lem-oil. This is something musicians use to protect wood surfaces on their instruments. It preserves the wood and tones down scratches and blemishes. After spraying the oil on the CD, he rubbed it vigorously with the lint-free cloth. Apparently, when he popped the CD into the player, it worked.
But the music didn’t sound right. In any case, lem-oil isn’t volatile enough to evaporate in five minutes. He dropped the idea and picked up toothpaste.
Now, the toothpaste method is something quite a few people have tried. It is a mild abrasive. So you take the tiniest bit of paste on the tip of your finger.
Without touching the CD itself with the finger, apply the toothpaste only around the scratched parts. Now put the CD under a thin stream of running water and tilt the CD. This way, the excess paste runs off and what remains gets into the CD. Apparently, his player spat the CD out.
A few other things later, he finally hit upon hair gel. Applied in much the same way toothpaste is, he followed up by rubbing it in and ran a thin stream of water on to loosen it up. This way, the excess gel was washed off. And the disc worked—perfectly.
http://infotech.indiatimes.com/Personal_Tech/Digital_Home/Saving_that_disk/articleshow/1979759.cms
Wednesday, May 30, 2007
Digital Sound
Everybody, including myself, was astonished to find that it was impossible to distinguish between my own voice, and Mr. Edison's re-creation of it.—Anna Case, Metropolitan Opera Soprano, 1915
In the July 1990 "As We See It" (Vol.13 No.7, p.5), I examined the conflict between those who believe existing measurements can reveal and quantify every audible aspect of a component's behavior, and those who consider the listening experience a far better indicator of a component's performance than the numbers generated by "objective" measurements. Implicit in the objectivist position is the assumption that phenomena affecting a device's audible characteristics are well understood: any mysteries have long since been crushed by the juggernaut of scientific method. If people then hear differences that "science" cannot measure or quantify, those differences exist only in people's minds and have no basis in reality. Consequently, observers' listening impressions are virtually excluded from consideration as merely "subjective," unworthy of acceptance by audio science. This belief structure is at the very core of the audio engineering establishment, and is the guiding force behind their research efforts (footnote 1).
The subjectivists believe that the ear is far superior to test instruments in resolving differences. It is also axiomatic that vast areas of audio reproduction, far from being fully researched and understood, are instead considerably more complex than the simple scientific models used to describe them.
A good example of this is the well-publicized subject of CD treatments. In the October issue (Vol.13 No.10, p.5) I described my experiences with cryogenically frozen CDs, as well as CDs pressed from the same stamper but made from different molding materials. I am particularly fascinated by CD treatments not for what they do, but for what they represent. The fact that cryogenically freezing a CD results in an easily audible change in sound points to the uncomfortable (for the engineering establishment) conclusion that everything is not as simple and well-understood as is thought.
A result of this dichotomy is that academic researchers—the very people in whose hands lie the tools and knowledge to discover the physical causes of these phenomena—are the least likely to listen critically and the most likely to dismiss the audiophile's claims as nothing more than voodoo. Consequently, their research direction is dictated by improving measured performance rather than increasing subjective performance; the latter is far more meaningful when the goal of research is to better communicate the musical experience.
Those who make their livings from digital audio (like mastering engineers) have long complained about sonic anomalies and perceptual differences where no differences should theoretically exist. The academic audio community, as well as manufacturers of professional digital audio equipment, maintain that these differences—unsupported by theory and unmeasurable—are products of the listeners' imaginations.
This thinking was exemplified by events during a two-day Sony seminar on digital mastering technology I attended a few years ago. The designers of the Sony PCM-1630, DAE-1100 digital editor, and other digital mastering equipment were present. The seminar was attended by mastering engineers who work with, and listen to, this equipment daily.
One of the mastering engineers expressed his concern over the audible degradation that occurs when making digital-to-digital tape copies, and the sonic differences introduced by the digital editor, especially when using the editor's level adjustment (footnote 2). These comments set off an outspoken flurry of concurrence among the assembled mastering engineers. The Sony designers argued vehemently that no differences were possible, and regarded the collective perception with some amusement. This exchange is a microcosm of the conflict between those who listen and those who measure.
Such is the background of this essay's subject, a paper by Dr. Roger Lagadec entitled "New Frontiers in Digital Audio" presented at the most recent Audio Engineering Society Convention in Los Angeles. I believe this paper will one day be considered a turning point in digital audio's evolution. Copernican in scope, it is likely to radically change the direction of and thinking in audio engineering. Lagadec's thesis is of utmost importance to the audiophile, both because of its promise of greatly improved digital audio, and for its validation of a fundamental audiophile philosophy: the importance of critical listening in evaluating audio technology over the belief that existing measurements can reveal all differences. Furthermore, and perhaps most significant, the paper was written by a man considered by many to be the world's foremost thinker in digital audio, whose ideas carry enormous influence in the audio engineering community.
As a pioneer in digital audio since 1973, Dr. Lagadec has conducted fundamental research into digital signal processing, was one of the developers of the Digital Audio Stationary Head (DASH) format while at Studer, and has offered broad, conceptual insights into the nature of digital audio. He holds a Ph.D. in Technical Sciences in the field of Digital Signal Processing, and has been actively involved in setting digital audio standards within the AES, of which he was named a Fellow in 1983. He is now responsible for all professional digital products at Sony. It is difficult to overstate Dr. Lagadec's credentials or his ability to influence digital-audio thinking.
"New Frontiers in Digital Audio" is bold in concept, brilliant in its simplicity, and technically incontrovertible. The paper identifies two areas of digital audio considered fully understood—digital-domain gain adjustment and dither—and reveals fundamental concepts about these areas that had not previously been considered (footnote 3). Moreover, the paper correlates these new discoveries with the perceptions of trained listeners whose comments were once considered heresy. Significantly, Dr. Lagadec's thesis extends beyond digital gain adjustment and dither: these two relatively simple issues are paradigms for the broader and more complex conflict between measurement and human musical perception. In this analysis, I will avoid most of the paper's technical details and focus instead on the broader issues raised (footnote 4).
Dr. Lagadec challenges the conventional wisdom that requantizing a digital audio signal with a digital fader produces only a change in level accompanied by a slight noise increase. "The imprecise, but by no means uncertain, answer of experienced users has sometimes been that—with critical signals—the texture of the new signal, its fine structure, possibly its precise spatial definition, will be affected: the signal will (sometimes) have changed in a way uncorrelated to level change and noise level, in spite of the extreme simplicity of the digital signal processing it underwent....The rest of this chapter cannot have the ambition of proving that such vague (but genuine) comments are true in an absolute sense. Rather, it will try to make the point that, based on a straightforward analysis, it is implausible that well-trained personnel would not detect differences beyond noise and signal level." (emphasis in original)
This, in itself, is a remarkably bold position for Dr. Lagadec to adopt. To acknowledge that previously unidentified phenomena affect the subjective perception of digitally processed music is indeed a milestone on the road to improving digital audio. Furthermore, the thesis doesn't summarily reject the listening experience as an important contributor to understanding these phenomena. The audio engineering establishment typically rejects listening because one's perceptions cannot be proven in a scientifically acceptable method and are therefore meaningless. It is also unusual for a man of science to use a lexicon associated more with audiophiles than scientists ("the texture of the new signal, its fine structure, possibly its precise spatial definition"). The audiophile, however, would have described these perceptions in more blunt terms; textures hard rather than liquid, loss of inner instrumental detail, and a collapsed soundstage.
Dr. Lagadec supports his thesis with a very simple analysis of what happens when changing level in the digital domain and the nature of the attendant requantization error. This function is considered perhaps the simplest and best-understood type of digital signal processing. However, he has discovered a previously unknown form of error created by this simple processing: the digital gain control's transfer function (difference between input and output signals) varies according to the amount of gain or attenuation. The nature of the transfer function's non-linearity (imprecision), introduced by changing gain in the digital domain, is determined by the gain pair ratios; ie, the relative beginning signal level and the signal level after gain reduction. I won't go into the details here: the phenomenon is explained and documented fully in the paper.
This discovery is extraordinary for two reasons. First, it vindicates those who have long maintained, after critical listening, that digital faders affect sound quality (footnote 5). Second and more important, it reveals that even the simplest aspects of digital audio that are thought to be well understood are, in fact, not well understood. Dr. Lagadec has worked for the past 7 of his 17 years in digital audio in the area of digital level control, yet recognized and began researching this phenomenon during only the past year. Again, I quote Dr. Lagadec's paper: "It is remarkable that such a simple system, eminently amenable to the methods used in non-linear dynamics, has not—to the author's limited knowledge—been widely publicized yet. If an element of surprise can come from analyzing such simple systems, more instructive surprises may be in store when more complex ones are scrutinized."
With this last sentence, Dr. Lagadec implies that a digital Pandora's Box may be opened by closer analysis of other aspects of digital audio. Like the Pandora's Box of Greek mythology that contained the world's troubles, this digital Pandora's Box may reveal other problems in digital audio that no one knew existed. An understanding of these cracks in conventional digital audio theory will go a long way toward correlating listeners' subjective impressions with objective fact.
The paper then examines dither, another area which, like digital gain adjustment, is considered a closed subject because it is well understood. Dr. Lagadec presents a hypothesis which states that dither should be optimized based on the ear's short-term perception of quantization noise, rather than the current mathematically based long-term analysis: "Needless to say, the 'optimal' dither types in the long-term statistical sense which have been proposed by Vanderkoy [sic] and Lipshitz (footnote 6) are a very valid first approach. As they are, however, independent of any practical detector model, it is not unfair to expect further improvements in perceived performance from dither models optimized in a different, less mathematically rigorous, and more perceptually oriented way."
With that analysis, Dr. Lagadec again proposes that an existing precept, thought to be immutable, is in fact far from a settled question. Moreover, one can infer that future research should be based on improving perceptual qualities rather than conforming to mathematical theories. This is reflected in the phrases "independent of any practical detector model" (my interpretation: "without regard for human hearing"), and "dither models optimized in a different, less mathematically rigorous, and more perceptually oriented way." (emphasis added)
Significantly, this suggests that the criterion for what is considered optimum dither should be based on human hearing rather than on purely mathematical ideas or measurements that have little relation to auditory perception (footnote 7). This represents a remarkable shift in thinking away from the scientific dictum that measurements and theory are more reliable and important than human perception in determining "what is good" in music reproduction. The human perceptual element in audio engineering has long been disregarded because it cannot be quantified. The ability to measure and quantify an entity are the criteria by which science judges that entity's reality. The scientific mind tends to mistrust anything than cannot be represented or communicated by linear symbols. These symbols that describe reality, obtained by measurement and calculation, assume a greater importance than, or are even mistaken for, the actual reality they try to represent. It is thus momentous that one of the world's foremost audio scientists has called for accepting musical perception directly rather than in the abstract, linear terms of representational thinking.
Dr. Lagadec points to some future directions in digital audio, including "a much greater word length" than the current 16-bit system, and bandwidth much wider than 20kHz. This additional bandwidth would be "kept open for, say, low-level harmonics, harmonics due to non-linear processing, and out-of-band noise shaping." An advantage he notes of having bandwidth beyond 20kHz "would be the freedom to disregard the arguments as to whether there is perceptible sound beyond 20kHz." However, he notes that "For economic reasons, it is evident that hardware capable of such parameters at an acceptable cost is not for this decade."
This concept of today's digital audio being in its infancy and subject to radical changes in fundamental precepts is in sharp contrast to the prevailing view among most academics that the 20kHz bandwidth is adequate, and that properly dithered 16-bit representation provides sufficient resolution and dynamic range. Indeed, the idea that today's digital audio parameters are perfectly satisfactory for music were expressed by Dr. Stanley Lipshitz parenthetically in his "Tutorial on Phase," given at the convention. He somewhat derisively scolded critics of digital audio for speciously (in his view) blaming today's digital audio's fundamental parameters (he specifically mentioned sampling rate and word length) as the cause of its inferiority (in the critics' view) to analog.
Dr. Lagadec then says that since the previously unknown aspects of digital audio he has discovered correlate to what critical listeners have been saying for years, perhaps other claims of audible differences should not be dismissed so cavalierly by the audio engineering establishment, despite the lack of scientific proof of such differences. I was astonished by the paper's last paragraphs (quoted below), in which Dr. Lagadec expands his thesis by bringing up the subject of audible differences between cables. Claims of differences between cables have long been a bugaboo of audio engineers. Further, he contends that if no measurable differences exist between cables, yet critical listeners report such differences, perhaps our understanding of human hearing acuity is suspect, rather than the rationality of those who hear differences.
The paper concludes by calling for the world's audio scientists and researchers to vigorously pursue these new challenges and to make room for, rather than exclude, the role of listening in advancing audio science. Dr. Lagadec writes:
"The industry is full of lore as to the superior sound quality of some cables, connectors, electronic devices, and the like. Assuming, as scientists presumably should, that things can only sound different if they cause signals to become different, and using the technology available today to ascertain whether differences do exist, and if so what they consist of, we may hope to achieve reproducible improvements; to deepen our understanding of sound quality; and to separate unfounded legends from justifiable improvements.
"Conversely, if we were to discover that, when, say, different cables are used, the signals look the same beyond the resolution of today's best converters, but still sound reproducibly different, then we would indeed still have much to learn about human audibility.
"The advanced tools available today—the recorders, computer software, workstations, DSP chips and boards, monitor systems, A/D and D/A conversion systems, instrumentation—and which are within reach of any university might be put to use, scientifically, aggressively, to find out how we hear, and how we might improve what we hear. Every generation since Edison's days has said that its sound recordings were almost better than the original, and at the very least indistinguishable from reality. Ours will hardly be an exception, neither in hubris and hype, nor in the disappointment. Yet we have tools for generating and manipulating signals, moving them in space and time, which few of our predecessors dreamed of. The tools deserve to be used, and our engineers deserve to be guided, by scientists who will advance the state of the art ahead of the state of the industry."
Although the tenets put forth in "New Frontiers in Digital Audio" are hardly new to audiophiles, the paper is revolutionary to the mindset of the audio engineering community. What makes this paper such a significant and extraordinary event is the credibility and influence of its author. You may be certain that Dr. Lagadec does not speak lightly or from a shaky platform. Consequently, the ideas expressed in the paper will be given serious consideration by those accustomed to attacking the very same ideas when espoused by those of us without Ph.Ds.
As I considered the paper's ramifications, I couldn't help thinking about the people who for years have reported sonic anomalies in digital audio, only to be met with skepticism and ridicule. This is especially true of Doug Sax, who was one of the first and most outspoken critics of digital. During the past eight years, he has reported his listening experiences to an indifferent world. Despite his pre-eminence in the field of record mastering, he is regarded as a pariah by the audio engineering community for his views, views which I believe have been taken a step toward scientific fact by "New Frontiers in Digital Audio."
If "genius" is defined as the arriving at conclusions ten years before the rest of the world reaches those same conclusions, then both Roger Lagadec and Doug Sax, disparate as their approaches are, certainly qualify. The fact that Dr. Lagadec's paper may cause the audio engineering establishment to take seriously the listening impressions of people like Doug Sax is small consolation to music lovers who must listen to inferior CDs made during the period between when the problems were first reported (1982) and when the problems' existence were proved in a scientifically acceptable method (1990).
"New Frontiers in Digital Audio" holds out the hope that one day digital audio may exceed analog's performance in all respects. It is my sincerest hope that our successors regard today's pronouncements of digital audio's quality with the same combination of humor and incredulity with which we view Anna Case's assessment of Mr. Edison's machine.
http://www.stereophile.com/asweseeit/1290awsi/
In the July 1990 "As We See It" (Vol.13 No.7, p.5), I examined the conflict between those who believe existing measurements can reveal and quantify every audible aspect of a component's behavior, and those who consider the listening experience a far better indicator of a component's performance than the numbers generated by "objective" measurements. Implicit in the objectivist position is the assumption that phenomena affecting a device's audible characteristics are well understood: any mysteries have long since been crushed by the juggernaut of scientific method. If people then hear differences that "science" cannot measure or quantify, those differences exist only in people's minds and have no basis in reality. Consequently, observers' listening impressions are virtually excluded from consideration as merely "subjective," unworthy of acceptance by audio science. This belief structure is at the very core of the audio engineering establishment, and is the guiding force behind their research efforts (footnote 1).
The subjectivists believe that the ear is far superior to test instruments in resolving differences. It is also axiomatic that vast areas of audio reproduction, far from being fully researched and understood, are instead considerably more complex than the simple scientific models used to describe them.
A good example of this is the well-publicized subject of CD treatments. In the October issue (Vol.13 No.10, p.5) I described my experiences with cryogenically frozen CDs, as well as CDs pressed from the same stamper but made from different molding materials. I am particularly fascinated by CD treatments not for what they do, but for what they represent. The fact that cryogenically freezing a CD results in an easily audible change in sound points to the uncomfortable (for the engineering establishment) conclusion that everything is not as simple and well-understood as is thought.
A result of this dichotomy is that academic researchers—the very people in whose hands lie the tools and knowledge to discover the physical causes of these phenomena—are the least likely to listen critically and the most likely to dismiss the audiophile's claims as nothing more than voodoo. Consequently, their research direction is dictated by improving measured performance rather than increasing subjective performance; the latter is far more meaningful when the goal of research is to better communicate the musical experience.
Those who make their livings from digital audio (like mastering engineers) have long complained about sonic anomalies and perceptual differences where no differences should theoretically exist. The academic audio community, as well as manufacturers of professional digital audio equipment, maintain that these differences—unsupported by theory and unmeasurable—are products of the listeners' imaginations.
This thinking was exemplified by events during a two-day Sony seminar on digital mastering technology I attended a few years ago. The designers of the Sony PCM-1630, DAE-1100 digital editor, and other digital mastering equipment were present. The seminar was attended by mastering engineers who work with, and listen to, this equipment daily.
One of the mastering engineers expressed his concern over the audible degradation that occurs when making digital-to-digital tape copies, and the sonic differences introduced by the digital editor, especially when using the editor's level adjustment (footnote 2). These comments set off an outspoken flurry of concurrence among the assembled mastering engineers. The Sony designers argued vehemently that no differences were possible, and regarded the collective perception with some amusement. This exchange is a microcosm of the conflict between those who listen and those who measure.
Such is the background of this essay's subject, a paper by Dr. Roger Lagadec entitled "New Frontiers in Digital Audio" presented at the most recent Audio Engineering Society Convention in Los Angeles. I believe this paper will one day be considered a turning point in digital audio's evolution. Copernican in scope, it is likely to radically change the direction of and thinking in audio engineering. Lagadec's thesis is of utmost importance to the audiophile, both because of its promise of greatly improved digital audio, and for its validation of a fundamental audiophile philosophy: the importance of critical listening in evaluating audio technology over the belief that existing measurements can reveal all differences. Furthermore, and perhaps most significant, the paper was written by a man considered by many to be the world's foremost thinker in digital audio, whose ideas carry enormous influence in the audio engineering community.
As a pioneer in digital audio since 1973, Dr. Lagadec has conducted fundamental research into digital signal processing, was one of the developers of the Digital Audio Stationary Head (DASH) format while at Studer, and has offered broad, conceptual insights into the nature of digital audio. He holds a Ph.D. in Technical Sciences in the field of Digital Signal Processing, and has been actively involved in setting digital audio standards within the AES, of which he was named a Fellow in 1983. He is now responsible for all professional digital products at Sony. It is difficult to overstate Dr. Lagadec's credentials or his ability to influence digital-audio thinking.
"New Frontiers in Digital Audio" is bold in concept, brilliant in its simplicity, and technically incontrovertible. The paper identifies two areas of digital audio considered fully understood—digital-domain gain adjustment and dither—and reveals fundamental concepts about these areas that had not previously been considered (footnote 3). Moreover, the paper correlates these new discoveries with the perceptions of trained listeners whose comments were once considered heresy. Significantly, Dr. Lagadec's thesis extends beyond digital gain adjustment and dither: these two relatively simple issues are paradigms for the broader and more complex conflict between measurement and human musical perception. In this analysis, I will avoid most of the paper's technical details and focus instead on the broader issues raised (footnote 4).
Dr. Lagadec challenges the conventional wisdom that requantizing a digital audio signal with a digital fader produces only a change in level accompanied by a slight noise increase. "The imprecise, but by no means uncertain, answer of experienced users has sometimes been that—with critical signals—the texture of the new signal, its fine structure, possibly its precise spatial definition, will be affected: the signal will (sometimes) have changed in a way uncorrelated to level change and noise level, in spite of the extreme simplicity of the digital signal processing it underwent....The rest of this chapter cannot have the ambition of proving that such vague (but genuine) comments are true in an absolute sense. Rather, it will try to make the point that, based on a straightforward analysis, it is implausible that well-trained personnel would not detect differences beyond noise and signal level." (emphasis in original)
This, in itself, is a remarkably bold position for Dr. Lagadec to adopt. To acknowledge that previously unidentified phenomena affect the subjective perception of digitally processed music is indeed a milestone on the road to improving digital audio. Furthermore, the thesis doesn't summarily reject the listening experience as an important contributor to understanding these phenomena. The audio engineering establishment typically rejects listening because one's perceptions cannot be proven in a scientifically acceptable method and are therefore meaningless. It is also unusual for a man of science to use a lexicon associated more with audiophiles than scientists ("the texture of the new signal, its fine structure, possibly its precise spatial definition"). The audiophile, however, would have described these perceptions in more blunt terms; textures hard rather than liquid, loss of inner instrumental detail, and a collapsed soundstage.
Dr. Lagadec supports his thesis with a very simple analysis of what happens when changing level in the digital domain and the nature of the attendant requantization error. This function is considered perhaps the simplest and best-understood type of digital signal processing. However, he has discovered a previously unknown form of error created by this simple processing: the digital gain control's transfer function (difference between input and output signals) varies according to the amount of gain or attenuation. The nature of the transfer function's non-linearity (imprecision), introduced by changing gain in the digital domain, is determined by the gain pair ratios; ie, the relative beginning signal level and the signal level after gain reduction. I won't go into the details here: the phenomenon is explained and documented fully in the paper.
This discovery is extraordinary for two reasons. First, it vindicates those who have long maintained, after critical listening, that digital faders affect sound quality (footnote 5). Second and more important, it reveals that even the simplest aspects of digital audio that are thought to be well understood are, in fact, not well understood. Dr. Lagadec has worked for the past 7 of his 17 years in digital audio in the area of digital level control, yet recognized and began researching this phenomenon during only the past year. Again, I quote Dr. Lagadec's paper: "It is remarkable that such a simple system, eminently amenable to the methods used in non-linear dynamics, has not—to the author's limited knowledge—been widely publicized yet. If an element of surprise can come from analyzing such simple systems, more instructive surprises may be in store when more complex ones are scrutinized."
With this last sentence, Dr. Lagadec implies that a digital Pandora's Box may be opened by closer analysis of other aspects of digital audio. Like the Pandora's Box of Greek mythology that contained the world's troubles, this digital Pandora's Box may reveal other problems in digital audio that no one knew existed. An understanding of these cracks in conventional digital audio theory will go a long way toward correlating listeners' subjective impressions with objective fact.
The paper then examines dither, another area which, like digital gain adjustment, is considered a closed subject because it is well understood. Dr. Lagadec presents a hypothesis which states that dither should be optimized based on the ear's short-term perception of quantization noise, rather than the current mathematically based long-term analysis: "Needless to say, the 'optimal' dither types in the long-term statistical sense which have been proposed by Vanderkoy [sic] and Lipshitz (footnote 6) are a very valid first approach. As they are, however, independent of any practical detector model, it is not unfair to expect further improvements in perceived performance from dither models optimized in a different, less mathematically rigorous, and more perceptually oriented way."
With that analysis, Dr. Lagadec again proposes that an existing precept, thought to be immutable, is in fact far from a settled question. Moreover, one can infer that future research should be based on improving perceptual qualities rather than conforming to mathematical theories. This is reflected in the phrases "independent of any practical detector model" (my interpretation: "without regard for human hearing"), and "dither models optimized in a different, less mathematically rigorous, and more perceptually oriented way." (emphasis added)
Significantly, this suggests that the criterion for what is considered optimum dither should be based on human hearing rather than on purely mathematical ideas or measurements that have little relation to auditory perception (footnote 7). This represents a remarkable shift in thinking away from the scientific dictum that measurements and theory are more reliable and important than human perception in determining "what is good" in music reproduction. The human perceptual element in audio engineering has long been disregarded because it cannot be quantified. The ability to measure and quantify an entity are the criteria by which science judges that entity's reality. The scientific mind tends to mistrust anything than cannot be represented or communicated by linear symbols. These symbols that describe reality, obtained by measurement and calculation, assume a greater importance than, or are even mistaken for, the actual reality they try to represent. It is thus momentous that one of the world's foremost audio scientists has called for accepting musical perception directly rather than in the abstract, linear terms of representational thinking.
Dr. Lagadec points to some future directions in digital audio, including "a much greater word length" than the current 16-bit system, and bandwidth much wider than 20kHz. This additional bandwidth would be "kept open for, say, low-level harmonics, harmonics due to non-linear processing, and out-of-band noise shaping." An advantage he notes of having bandwidth beyond 20kHz "would be the freedom to disregard the arguments as to whether there is perceptible sound beyond 20kHz." However, he notes that "For economic reasons, it is evident that hardware capable of such parameters at an acceptable cost is not for this decade."
This concept of today's digital audio being in its infancy and subject to radical changes in fundamental precepts is in sharp contrast to the prevailing view among most academics that the 20kHz bandwidth is adequate, and that properly dithered 16-bit representation provides sufficient resolution and dynamic range. Indeed, the idea that today's digital audio parameters are perfectly satisfactory for music were expressed by Dr. Stanley Lipshitz parenthetically in his "Tutorial on Phase," given at the convention. He somewhat derisively scolded critics of digital audio for speciously (in his view) blaming today's digital audio's fundamental parameters (he specifically mentioned sampling rate and word length) as the cause of its inferiority (in the critics' view) to analog.
Dr. Lagadec then says that since the previously unknown aspects of digital audio he has discovered correlate to what critical listeners have been saying for years, perhaps other claims of audible differences should not be dismissed so cavalierly by the audio engineering establishment, despite the lack of scientific proof of such differences. I was astonished by the paper's last paragraphs (quoted below), in which Dr. Lagadec expands his thesis by bringing up the subject of audible differences between cables. Claims of differences between cables have long been a bugaboo of audio engineers. Further, he contends that if no measurable differences exist between cables, yet critical listeners report such differences, perhaps our understanding of human hearing acuity is suspect, rather than the rationality of those who hear differences.
The paper concludes by calling for the world's audio scientists and researchers to vigorously pursue these new challenges and to make room for, rather than exclude, the role of listening in advancing audio science. Dr. Lagadec writes:
"The industry is full of lore as to the superior sound quality of some cables, connectors, electronic devices, and the like. Assuming, as scientists presumably should, that things can only sound different if they cause signals to become different, and using the technology available today to ascertain whether differences do exist, and if so what they consist of, we may hope to achieve reproducible improvements; to deepen our understanding of sound quality; and to separate unfounded legends from justifiable improvements.
"Conversely, if we were to discover that, when, say, different cables are used, the signals look the same beyond the resolution of today's best converters, but still sound reproducibly different, then we would indeed still have much to learn about human audibility.
"The advanced tools available today—the recorders, computer software, workstations, DSP chips and boards, monitor systems, A/D and D/A conversion systems, instrumentation—and which are within reach of any university might be put to use, scientifically, aggressively, to find out how we hear, and how we might improve what we hear. Every generation since Edison's days has said that its sound recordings were almost better than the original, and at the very least indistinguishable from reality. Ours will hardly be an exception, neither in hubris and hype, nor in the disappointment. Yet we have tools for generating and manipulating signals, moving them in space and time, which few of our predecessors dreamed of. The tools deserve to be used, and our engineers deserve to be guided, by scientists who will advance the state of the art ahead of the state of the industry."
Although the tenets put forth in "New Frontiers in Digital Audio" are hardly new to audiophiles, the paper is revolutionary to the mindset of the audio engineering community. What makes this paper such a significant and extraordinary event is the credibility and influence of its author. You may be certain that Dr. Lagadec does not speak lightly or from a shaky platform. Consequently, the ideas expressed in the paper will be given serious consideration by those accustomed to attacking the very same ideas when espoused by those of us without Ph.Ds.
As I considered the paper's ramifications, I couldn't help thinking about the people who for years have reported sonic anomalies in digital audio, only to be met with skepticism and ridicule. This is especially true of Doug Sax, who was one of the first and most outspoken critics of digital. During the past eight years, he has reported his listening experiences to an indifferent world. Despite his pre-eminence in the field of record mastering, he is regarded as a pariah by the audio engineering community for his views, views which I believe have been taken a step toward scientific fact by "New Frontiers in Digital Audio."
If "genius" is defined as the arriving at conclusions ten years before the rest of the world reaches those same conclusions, then both Roger Lagadec and Doug Sax, disparate as their approaches are, certainly qualify. The fact that Dr. Lagadec's paper may cause the audio engineering establishment to take seriously the listening impressions of people like Doug Sax is small consolation to music lovers who must listen to inferior CDs made during the period between when the problems were first reported (1982) and when the problems' existence were proved in a scientifically acceptable method (1990).
"New Frontiers in Digital Audio" holds out the hope that one day digital audio may exceed analog's performance in all respects. It is my sincerest hope that our successors regard today's pronouncements of digital audio's quality with the same combination of humor and incredulity with which we view Anna Case's assessment of Mr. Edison's machine.
http://www.stereophile.com/asweseeit/1290awsi/
Frozen CDs?
Just when you thought it was safe to put green paint around the edges of your CDs without ridicule, there's yet another CD tweak that's sure to bring howls of laughter from the skeptics: cryogenically freezing CDs. They won't be laughing for long, however, when they hear for themselves the sonic results of this process.
Ed Meitner, designer of the Museatex line of electronics, has discovered that cryogenically freezing a CD changes the physical structure of polycarbonate, the plastic material from which CDs are made. The result is reportedly an audible improvement in sound quality. In this process, CDs are placed in a cryogenic freezing chamber and the temperature is slowly reduced over eight hours to 75 Kelvins, or about -300 degrees Fahrenheit. This is approximately the temperature of liquid nitrogen, the chamber's cooling agent. The temperature is then slowly brought back to room temperature over another eight hours.
This technique reportedly relaxes the lattice structure of a material (polycarbonate in the case of CD) that has been previously distorted by heat or pressure, both of which are present during CD injection molding. By reducing the molecular bonds holding the material together, the internal stress in the material is reduced, thus changing its resonant characteristics. Indeed, a treated disc feels slightly more flexible than an untreated disc.
But how could freezing a CD possibly affect its sound quality? So what if the polycarbonate has a different structure? The data are all ones and zeros. Furthermore, uncorrected data errors are almost nonexistent in most discsci without treatment, ruling out improved data integrity as an answer. I posed these questions to Ed Meitner and got the following explanation (footnote 1).
Mechanical vibration of the disc causes the HF signal to become noisy and have excessive jitter. The HF signal is the raw signal output from the CD player's photodetector (footnote 2). By freezing a CD, the disc's mechanical resonance is lowered, improving the quality of the HF signal retrieved from the disc. Although theory states that noise and jitter in the HF signal will have no effect on sound quality—the HF signal is squared, buffered, decoded, filtered, and clocked out of another buffer with quartz-crystal accuracy—many digital designers maintain that HF signal quality does affect the sound.
Ed Meitner claims that the HF signal improvement from a cryogenically treated disc is easily measurable. I looked at the HF signal on an oscilloscope from the Esoteric P2 transport with treated and untreated discs. I could see no difference in the signal quality. However, it is very difficult to make comparisons without seeing the two HF signals side by side.
Meitner is talking to some audiophile labels about mass-treating their releases. Apparently, the process is efficient and economical, with the ability to treat thousands of discs at once. Liquid nitrogen, which doesn't come in direct contact with the CDs, is inexpensive and readily available. Interestingly, this process is said to yield similar sonic improvements with a vinyl phonograph record. In addition to CDs and LPs, the process has been used on LaserVision-format video discs, speaker cable, interconnects, integrated circuits, and musical instrument strings.
Cryogenic freezing is also used to treat machine tools like drill bits, copper welding tools, and saw blades. The process reportedly improves their wear characteristics, thus extending the tool's useful life. The treatment doesn't always work, however, and there is no consensus among metallurgists that the process is always beneficial. In fact, the effects of cryogenically freezing materials is not well understood; little scientific research has been done to explain the phenomenon (footnote 3).
Another tweak developed by Ed Meitner is painting a CD's top surface black. This reportedly improves sound quality by improving the signal at the CD player's photodetector. Before describing how this works, let's look at the playback laser beam's path through the disc.
The playback beam enters the disc through the surface without the label. It travels through the 1.2mm disc thickness where it encounters pits impressed in the polycarbonate. To reflect the beam back through the disc and to the photodetector, a thin layer of aluminum is deposited on the disc surface, which conforms to the pit structure. A protective coating of varnish seals in the aluminum and prevents it from oxidizing. The label is then silk-screened on top of the protective coating.
Ed Meitner contends that several mechanisms are at work that degrade the HF signal picked up by the photodetector. One phenomenon is distortion of the aluminum layer by the laser beam's heat. Even though the beam is very low-power—about half a milliwatt—it is focused on such a small area (1.5µm) that the aluminum molecules bend, causing the aluminum layer to flex. This introduces jitter in the HF signal as well as noise in the focus signal.
This phenomenon has reportedly been measured by painting black bars on a CD's top surface (the label side) and looking at various signals. The bar pattern is readily apparent in both the focus servo and HF signals. Painting the CD black reportedly improves the thermal conditions by reducing the contrast in the aluminum molecules caused by laser-induced heat. Another mechanism that is also affected by black paint is the secondary reflection from the disc label. Some laser light passes through the aluminum layer and is reflected to the photodetector by the label. This reportedly causes noise in the HF signal which is manifested as uncertainty in the digital code transitions. Note that the above descriptions are those of Ed Meitner, and have not been independently verified.
How plausible are these explanations? I find some of them hard to believe, especially this last phenomenon. However, there is so much going on in digital audio that we don't know about—especially the optical considerations in data retrieval from CD—that I hesitate to rule out anything (footnote 4).
What really matters is if these treatments work. Since I believe that the ear is the highest-resolution instrument available to explore these phenomena, I gave Ed Meitner three copies of the Stereophile Test CD for treatment. One disc was cryogenically frozen, another was painted black, and the third was both painted and frozen. The Stereophile Test CD is ideal for this purpose: it has a wide variety of music, all recorded by Stereophile contributors. In addition, I know with absolute certainty that the three treated discs as well as my untreated control disc were made by JVC from the same master tape and CD stamper.
I began by listening to my guitar and bass recording from the untreated disc. After switching to the frozen and painted disc, the difference was immediate and obvious. First, the guitar appeared to become louder, with more clarity and detail. Subtle sounds like finger noises and minute instrumental detail jumped forward. The sonic picture became more vivid and immediate. The acoustic bass took on a more rounded character and its musical contribution seemed enhanced. There was a greater degree of air and life around the instruments; they suddenly became more palpable.
The degree to which these characteristics were apparent varied considerably with the type of music. During our annual Stereophile writers' conference in early August, I had an opportunity to play treated and untreated discs for some of the visiting writers. Arnis Balgalvis correctly identified the treated disc in a blind A/B/A comparison when he visited my listening room. He immediately knew that presentation B was different, and his description of the difference was remarkably similar to my impressions.
I repeated the blind test for Peter Mitchell in JA's listening room; Peter also immediately identified the treated disc. In fact, within seconds of hearing the treated disc with the guitar and bass recording, he let out a loud exclamation of surprise. His impressions were consistent with the differences I had heard, which I related to him after the test and his description to me of the differences.
A good point Peter raised was that although there was clearly a difference, he had doubts about which was "better" or more true to the original recording. The treated disc had a brighter, more detailed character that would exacerbate many of CD's problems.
The above listening comparisons were made between an untreated disc and one that was both cryogenically frozen and painted black. Further listening of frozen-only discs and painted-only discs revealed that most of the sonic difference was the result of freezing. The black paint, however, did add to the effect. A second frozen and painted disc sent to me by Museatex had similar differences. However, a look at the disc's inside ring, where the production number is written, revealed that it was a different pressing from my untreated control disc. I would therefore refrain from reaching any conclusions based on this disc. From my experience with the Stereophile Test CD, however, I am convinced that some unexplained phenomena are occurring in frozen and painted CDs.
http://www.stereophile.com/asweseeit/822/index1.html
Ed Meitner, designer of the Museatex line of electronics, has discovered that cryogenically freezing a CD changes the physical structure of polycarbonate, the plastic material from which CDs are made. The result is reportedly an audible improvement in sound quality. In this process, CDs are placed in a cryogenic freezing chamber and the temperature is slowly reduced over eight hours to 75 Kelvins, or about -300 degrees Fahrenheit. This is approximately the temperature of liquid nitrogen, the chamber's cooling agent. The temperature is then slowly brought back to room temperature over another eight hours.
This technique reportedly relaxes the lattice structure of a material (polycarbonate in the case of CD) that has been previously distorted by heat or pressure, both of which are present during CD injection molding. By reducing the molecular bonds holding the material together, the internal stress in the material is reduced, thus changing its resonant characteristics. Indeed, a treated disc feels slightly more flexible than an untreated disc.
But how could freezing a CD possibly affect its sound quality? So what if the polycarbonate has a different structure? The data are all ones and zeros. Furthermore, uncorrected data errors are almost nonexistent in most discsci without treatment, ruling out improved data integrity as an answer. I posed these questions to Ed Meitner and got the following explanation (footnote 1).
Mechanical vibration of the disc causes the HF signal to become noisy and have excessive jitter. The HF signal is the raw signal output from the CD player's photodetector (footnote 2). By freezing a CD, the disc's mechanical resonance is lowered, improving the quality of the HF signal retrieved from the disc. Although theory states that noise and jitter in the HF signal will have no effect on sound quality—the HF signal is squared, buffered, decoded, filtered, and clocked out of another buffer with quartz-crystal accuracy—many digital designers maintain that HF signal quality does affect the sound.
Ed Meitner claims that the HF signal improvement from a cryogenically treated disc is easily measurable. I looked at the HF signal on an oscilloscope from the Esoteric P2 transport with treated and untreated discs. I could see no difference in the signal quality. However, it is very difficult to make comparisons without seeing the two HF signals side by side.
Meitner is talking to some audiophile labels about mass-treating their releases. Apparently, the process is efficient and economical, with the ability to treat thousands of discs at once. Liquid nitrogen, which doesn't come in direct contact with the CDs, is inexpensive and readily available. Interestingly, this process is said to yield similar sonic improvements with a vinyl phonograph record. In addition to CDs and LPs, the process has been used on LaserVision-format video discs, speaker cable, interconnects, integrated circuits, and musical instrument strings.
Cryogenic freezing is also used to treat machine tools like drill bits, copper welding tools, and saw blades. The process reportedly improves their wear characteristics, thus extending the tool's useful life. The treatment doesn't always work, however, and there is no consensus among metallurgists that the process is always beneficial. In fact, the effects of cryogenically freezing materials is not well understood; little scientific research has been done to explain the phenomenon (footnote 3).
Another tweak developed by Ed Meitner is painting a CD's top surface black. This reportedly improves sound quality by improving the signal at the CD player's photodetector. Before describing how this works, let's look at the playback laser beam's path through the disc.
The playback beam enters the disc through the surface without the label. It travels through the 1.2mm disc thickness where it encounters pits impressed in the polycarbonate. To reflect the beam back through the disc and to the photodetector, a thin layer of aluminum is deposited on the disc surface, which conforms to the pit structure. A protective coating of varnish seals in the aluminum and prevents it from oxidizing. The label is then silk-screened on top of the protective coating.
Ed Meitner contends that several mechanisms are at work that degrade the HF signal picked up by the photodetector. One phenomenon is distortion of the aluminum layer by the laser beam's heat. Even though the beam is very low-power—about half a milliwatt—it is focused on such a small area (1.5µm) that the aluminum molecules bend, causing the aluminum layer to flex. This introduces jitter in the HF signal as well as noise in the focus signal.
This phenomenon has reportedly been measured by painting black bars on a CD's top surface (the label side) and looking at various signals. The bar pattern is readily apparent in both the focus servo and HF signals. Painting the CD black reportedly improves the thermal conditions by reducing the contrast in the aluminum molecules caused by laser-induced heat. Another mechanism that is also affected by black paint is the secondary reflection from the disc label. Some laser light passes through the aluminum layer and is reflected to the photodetector by the label. This reportedly causes noise in the HF signal which is manifested as uncertainty in the digital code transitions. Note that the above descriptions are those of Ed Meitner, and have not been independently verified.
How plausible are these explanations? I find some of them hard to believe, especially this last phenomenon. However, there is so much going on in digital audio that we don't know about—especially the optical considerations in data retrieval from CD—that I hesitate to rule out anything (footnote 4).
What really matters is if these treatments work. Since I believe that the ear is the highest-resolution instrument available to explore these phenomena, I gave Ed Meitner three copies of the Stereophile Test CD for treatment. One disc was cryogenically frozen, another was painted black, and the third was both painted and frozen. The Stereophile Test CD is ideal for this purpose: it has a wide variety of music, all recorded by Stereophile contributors. In addition, I know with absolute certainty that the three treated discs as well as my untreated control disc were made by JVC from the same master tape and CD stamper.
I began by listening to my guitar and bass recording from the untreated disc. After switching to the frozen and painted disc, the difference was immediate and obvious. First, the guitar appeared to become louder, with more clarity and detail. Subtle sounds like finger noises and minute instrumental detail jumped forward. The sonic picture became more vivid and immediate. The acoustic bass took on a more rounded character and its musical contribution seemed enhanced. There was a greater degree of air and life around the instruments; they suddenly became more palpable.
The degree to which these characteristics were apparent varied considerably with the type of music. During our annual Stereophile writers' conference in early August, I had an opportunity to play treated and untreated discs for some of the visiting writers. Arnis Balgalvis correctly identified the treated disc in a blind A/B/A comparison when he visited my listening room. He immediately knew that presentation B was different, and his description of the difference was remarkably similar to my impressions.
I repeated the blind test for Peter Mitchell in JA's listening room; Peter also immediately identified the treated disc. In fact, within seconds of hearing the treated disc with the guitar and bass recording, he let out a loud exclamation of surprise. His impressions were consistent with the differences I had heard, which I related to him after the test and his description to me of the differences.
A good point Peter raised was that although there was clearly a difference, he had doubts about which was "better" or more true to the original recording. The treated disc had a brighter, more detailed character that would exacerbate many of CD's problems.
The above listening comparisons were made between an untreated disc and one that was both cryogenically frozen and painted black. Further listening of frozen-only discs and painted-only discs revealed that most of the sonic difference was the result of freezing. The black paint, however, did add to the effect. A second frozen and painted disc sent to me by Museatex had similar differences. However, a look at the disc's inside ring, where the production number is written, revealed that it was a different pressing from my untreated control disc. I would therefore refrain from reaching any conclusions based on this disc. From my experience with the Stereophile Test CD, however, I am convinced that some unexplained phenomena are occurring in frozen and painted CDs.
http://www.stereophile.com/asweseeit/822/index1.html
CD: Jitter, Errors & Magic
The promise of "perfect sound forever," successfully foisted on an unwitting public by the Compact Disc's promoters, at first seemed to put an end to the audiophile's inexorable need to tweak a playback system's front end at the point of information retrieval. Several factors contributed to the demise of tweaking during the period when CD players began replacing turntables as the primary front-end signal source. First, the binary nature (ones and zeros) of digital audio would apparently preclude variations in playback sound quality due to imperfections in the recording medium. Second, if CD's sound was indeed "perfect," how could digital tweaking improve on perfection? Finally, CD players and discs presented an enigma to audiophiles accustomed to the more easily understood concept of a stylus wiggling in a phonograph groove. These conditions created a climate in which it was assumed that nothing in the optical and mechanical systems of a CD player could affect digital playback's musicality.
Recently, however, there has been a veritable explosion of interest in all manner of CD tweaks, opening a digital Pandora's box. An avalanche of CD tweak products (and the audiophile's embrace of them) has suddenly appeared in the past few months, Monster Cable's, AudioQuest's, and Euphonic Technology's CD Soundrings notwithstanding. Most of these tweaks would appear to border on voodoo, with no basis in scientific fact. Green marking pens, an automobile interior protectant, and an "optical impedance matching" fluid are just some of the products touted as producing musical nirvana. The popular media has even picked up on this phenomenon, sparked by Sam Tellig's Audio Anarchist column in Vol.13 No.2 describing the sonic benefits of applying Armor All, the automobile treatment, to a CD's surface. Print articles have appeared in the Los Angeles Times, Ice Magazine, and on television stations MTV, VH-1, and CNN, all reporting, with varying degrees of incredulity, the CD tweaking phenomenon.
The intensity of my interest in the subject was heightened by a product called "CD Stoplight," marketed by AudioPrism. CD Stoplight is a green paint applied to the outside edge of a CD (not the disc surface, but the 1.2mm disc thickness) that reportedly improves sound quality. I could not in my wildest imagination see how green paint on the disc edge could change, for better or worse, a CD's sound. However, trusting my ears as the definitive test, I compared treated to untreated discs and was flabbergasted. Soundstage depth increased, mids and highs were smoother with less grain, and the presentation became more musically involving.
Other listeners, to a person, have had similar impressions. Since I am somewhat familiar with the mechanisms by which data are retrieved from a CD (I worked in CD mastering for three years before joining Stereophile), this was perplexing: I could think of no plausible explanation for a difference in sonic quality. As we shall see, the light reflected from a CD striking the photo-detector contains all the information encoded on the disc (footnote 1). Even if CD Stoplight could somehow affect the light striking the photo-detector, how could this change make the soundstage deeper? I was simultaneously disturbed and encouraged by this experience. Disturbed because it illustrates our fundamental lack of understanding of digital audio's mysteries, and encouraged by the promise that identification of previously unexplored phenomena could improve digital audio to the point where today's digital audio era will be regarded as the stone age.
These events prompted me to conduct a scientific examination of several CD "sonic cure-all" devices and treatments. I wanted to find an objective, measurable phenomenon that explains the undeniable musical differences heard by many listeners where, at least according to established digital audio theory, no differences should exist. For this inquiry, I measured several digital-domain performance criteria on untreated CDs, and then on the same CDs treated with various CD tweaks. The parameters measured include data error rates, ability to correct (rather than conceal) data errors, and jitter.
The six CD treatments and devices chosen for this experiment include three that allegedly affect optical phenomena and three that ostensibly affect the CD player's mechanical performance. The three optical treatments tested are CD Stoplight (the green paint), Finyl (a liquid applied to a disc surface, that, according to its promoters, provides "optical impedance matching"), and Armor All. The mechanical devices include CD Soundrings, The Mod Squad's CD Damper disc, and the Arcici LaserBase, a vibration-absorbing CD-player platform. I also measured playback signal jitter in a mid-priced CD player and the $4000 Esoteric P2 transport (regarded as having superb sonics). However, this is not intended as a survey of the musical benefits of these devices and treatments. In addition, I looked at the variation in quality of discs made at various CD manufacturing facilities around the world.
Another purpose of the article is to dispel some common misconceptions about CD error correction and its effect on sonic quality. If one believes the promoters of some of these CD treatments, errors are the single biggest source of sonic degradation in digital audio. In reality, errors are the least of CD's problems. However, this has not prevented marketeers from exploiting the audiophile's errorphobia in an attempt to sell products.
For example, Digital Systems and Solutions, Inc., manufacturer of Finyl, claim in their white paper that error concealment "results in a serious degrading of playback fidelity." They also state that errors can get through undetected, leading to a litany of sonic horrors including: "poor articulation of bass and mid-bass notes, attenuation of dynamics and smearing of transients, increased noise with loss of inner detail and intertransient silence, reduced midrange presence that diminishes clarity and transparency, loss of image specificity and focus, reduction of the apparent width and depth of soundstage—virtually eliminating the possibility of holophonic [sic] imagery, decreased resolution of the low level detail that is so necessary to the recovery of hall ambience, altered instrumental and vocal timbres that lack coherence or cohesiveness, obscuring of vocal textures and expression, instrumental lines and musical themes are more difficult to sort out, complex rhythms and tempos are less easily followed, the music will not be as emotionally involving and satisfying an experience as might have otherwise been possible, subtle breath effects on brass or wind instruments are more difficult to discern as are nuances of fingering and bowing on string instruments." This list, they concede, "is not claimed to be complete."
Technical background
Encoding and data retrieval: Before getting into the measurement results, let's arm ourselves with a little technical background on how the CD works.
A CD's surface is covered by a single spiral track of alternating "pit" and "land" formations. These structures, which encode binary data, are created during the laser mastering process. The CD master disc is a glass substrate coated with a very thin layer of photosensitive material. The glass master is rotated on a turntable while exposed to a laser beam that is modulated (turned on and off) by the digital data we wish to record on the disc. This creates a spiral of exposed and unexposed areas of the disc. When the master is later put under a chemical developing solution, areas of the photosensitive material exposed to the recording laser beam are etched away, creating a pit. Unexposed areas are unaffected by the developing solution and are called lands. These formations, which are among the smallest manufactured structures, are transferred through the manufacturing process to mass-produced discs. Fig.1 is a scanning electron microscope of a CD surface. Note that a human hair is about the width of 50 tracks.
The playback laser beam in the CD player is focused on these tiny pits and held on track by a servo system as the disc rotates. This beam is reflected from the disc to a photo-detector, a device that converts light into voltage. To distinguish between pit and land areas, the pit depth is one-quarter the wavelength of the playback laser beam. When laser light strikes a pit, a portion of the beam is reflected from the surrounding land, while some light is reflected from the pit bottom. Since the portion of light reflected from the pit bottom must travel a longer distance (1/4 wavelength down plus 1/4 wavelength back up), this portion of the beam is delayed by half a wavelength in relation to the beam reflected by the land. When these two beams combine, phase cancellation occurs, resulting in decreased output from the photo-detector. This variable-intensity beam thus contains all the information encoded on the disc.
Now that we understand how the playback beam/photo-detector can distinguish between pit and land, let's look at how these distinctions represent digital audio data. One may intuitively think that it would be logical for a pit to represent binary one and a land to represent binary zero, or vice versa. This method would certainly work, but a much more sophisticated scheme has been devised that is fundamental to the CD. It is called Eight-to-Fourteen Modulation, or EFM.
This encoding system elegantly solves a variety of data-retrieval functions. In EFM encoding, pit and land do not represent binary data directly. Instead, transitions from pit-to-land or land-to-pit represent binary one, while all other surfaces (land or pit bottom) represent binary zero. EFM encoding takes symbols of 8 bits and converts them into unique 14-bit words, creating a pattern in which binary ones are separated by a minimum of two zeros and a maximum of 10 zeros. The bit stream is thus given a specific pattern of ones and zeros that result in nine discrete pit or land lengths on the disc. The shortest pit or land length encodes three bits, while the longest encodes 11 bits. The blocks of 14 bits are linked by three "merging bits," resulting in an encoding ratio of 17:8. At first glance, it may seem odd that EFM encoding, in more than doubling the number of bits to be stored, can actually increase data density. But just this occurs: Storage density is increased by 25% over unmodulated encoding.
EFM has other inherent advantages. By inserting zeros between successive ones, the bandwidth of the signal reflected from the disc is decreased. The data rate from a CD is 4.3218 million bits per second (footnote 2), but the EFM signal has a bandwidth of only 720kHz. In addition, the EFM signal serves as a clock that, among other functions, controls the player's rotational servo.
The signal reflected from the disc is comprised of nine discrete frequencies, corresponding to the nine discrete pit or land lengths (footnote 3). The highest-frequency component, called "I3," is produced by the shortest pit or land length and has a frequency of 720kHz. This represents binary data 100. The lowest-frequency component, called "I11," is produced by the longest pit or land length and has a frequency of 193kHz. This represents binary data 10000000000. The signal reflected from the disc, produced by EFM encoding, is often called the HF (high frequency) signal. The varying periods of the sinewaves correspond to the periods of time required to read the various pit lengths.
At first impression, the HF signal appears to be analog, not one that carries digital data. However, the zero crossings of the waveforms contain the digital information encoded on the disc. Fig.2 shows the relationship between binary data, pit structure, and the recovered HF signal.
Fig.2 Relationship between binary data, pit structure, and the HF signal. (Reproduced from Principles of Digital Audio, Second Edition (1989), by Kenneth C. Pohlmann, with the permission of the publisher, Howard W. Sams & Company.)
HF signal quality is a direct function of pit shape, which in turn is affected by many factors during the CD manufacturing process. There is a direct correlation between error rates and pit shape. Poorly shaped pits result in a low-amplitude HF signal with poorly defined lines. Figs.3 and 4 show an excellent HF signal and a poor HF signal respectively.
CD data errors: Any digital storage medium is prone to data errors, and the CD is no exception. An error occurs when a binary one is mistakenly read as a binary zero (or vice versa), or when the data flow is momentarily interrupted. The latter, more common in CDs, is caused by manufacturing defects, surface scratches, and dirt or other foreign particles on the disc. Fortunately, the CD format incorporates extremely powerful error detection and correction codes that can completely correct a burst error of up to 4000 successive bits. The reconstructed data are identical to what was missing. This is called error correction. If the data loss exceeds the player's ability to correctly replace missing data, the player makes a best-guess estimate of the missing data and inserts this approximation into the data stream. This is called error concealment, or interpolation.
It is important to make the distinction between correction and concealment: correction is perfect and inaudible, while concealment has the potential for a momentary sonic degradation where the interpolation occurs.
A good general indication of disc quality (and the claimed error-reduction effects of some CD tweaks) is the Block Error Rate, or BLER. BLER is the number of blocks per second that contain errant data, before error correction. The raw data stream from a CD (called "channel bits") contains 7350 blocks per second, with a maximum allowable BLER (as specified by Philips) of 220. A disc with a BLER of 100 thus has 100 blocks out of 7350 with errant or missing data. In these experiments, Block Error Rate is the primary indicator of a particular tweak's effect on error-rate performance.
In addition to measuring the effects of CD tweaks on BLER, I explored their potential to reduce interpolations. To do this, I used the Pierre Verany test CD that has intentional dropouts in the spiral track. The disc has a sequence of tracks with increasingly long periods of missing data.
First, I found the track that was just above the threshold of producing an uncorrectable error (called an "E23 error") as analyzed by the Design Science CD Analyzer (see Sidebar). The track was played repeatedly to assure consistency, thus avoiding the ascription to chance of any subsequent change. Then, the same track was played and analyzed, this time after the addition of a CD treatment or device. This twofold approach—measuring a tweak's effect on both BLER and interpolations—would seem to cover the gamut of error-reduction potential.
There are two general misconceptions about CD errors and sound quality: 1) errors are the primary source of sonic degradation; and 2) if there are no uncorrectable errors, there can be no difference in sound.
The first conclusion is largely due to the marketing programs of CD-accessory manufacturers who claim their products reduce error rates. Many of the devices tested claim to improve sound quality by reducing the amount of error concealment performed by the CD player. In fact, interpolations (error concealment) rarely occur. In the unlikely event that concealment is performed, it will be momentary and thus have no effect on the overall sound. At worst, a transient tick or glitch would be audible.
To better understand the nature of data errors, a look at CD Read-Only Memory (CD-ROM) is useful. A CD-ROM is manufactured just like an audio CD, but contains computer data (text, graphics, application software, etc.) instead of music. The data retrieved from a CD-ROM must be absolutely accurate to the bit level, after error correction. If even a single wrong bit gets past the error correction, the entire program could crash. The errant bit may be within instructions for the host computer's microprocessor, causing the whole application to come to an instant halt, making the disc useless.
To prevent this, a quality-control procedure is routinely used at the mastering and pressing facility to assure 100% error-free performance. Samples of the finished CD-ROM are compared, bit for bit, to the original source data. For high-reliability applications, each replicated disc undergoes this process. This rigorous testing reveals much about the error-correction ability of the CD's Cross Interleaved Reed-Solomon encoding (CIRC). Throughout dozens of hours of this verification procedure, I cannot remember even a single instance of one wrong bit getting through.
It could be argued that CD-ROM has additional error-correction ability not found on CD audio discs. This is true, but the additional layer of error correction is almost never invoked. Furthermore, in all the hours of error-rate measuring for this project, I never encountered an E23 error, the first and most sensitive indication of an interpolation (except on the Pierre Verany disc, which has intentional errors). In fact, I saw only one E22 error, the last stage of correction before concealment. In retesting the disc, the E22 error disappeared, indicating it was probably due to a piece of dirt on the disc. Finally, the unlikely occurrence of an uncorrectable error is exemplified by the warning system in the Design Science CD Analyzer. The system beeps and changes the computer's display color to red to alert the operator if even an E22 error (fully corrected) is detected.
http://www.stereophile.com/reference/590jitter/
Recently, however, there has been a veritable explosion of interest in all manner of CD tweaks, opening a digital Pandora's box. An avalanche of CD tweak products (and the audiophile's embrace of them) has suddenly appeared in the past few months, Monster Cable's, AudioQuest's, and Euphonic Technology's CD Soundrings notwithstanding. Most of these tweaks would appear to border on voodoo, with no basis in scientific fact. Green marking pens, an automobile interior protectant, and an "optical impedance matching" fluid are just some of the products touted as producing musical nirvana. The popular media has even picked up on this phenomenon, sparked by Sam Tellig's Audio Anarchist column in Vol.13 No.2 describing the sonic benefits of applying Armor All, the automobile treatment, to a CD's surface. Print articles have appeared in the Los Angeles Times, Ice Magazine, and on television stations MTV, VH-1, and CNN, all reporting, with varying degrees of incredulity, the CD tweaking phenomenon.
The intensity of my interest in the subject was heightened by a product called "CD Stoplight," marketed by AudioPrism. CD Stoplight is a green paint applied to the outside edge of a CD (not the disc surface, but the 1.2mm disc thickness) that reportedly improves sound quality. I could not in my wildest imagination see how green paint on the disc edge could change, for better or worse, a CD's sound. However, trusting my ears as the definitive test, I compared treated to untreated discs and was flabbergasted. Soundstage depth increased, mids and highs were smoother with less grain, and the presentation became more musically involving.
Other listeners, to a person, have had similar impressions. Since I am somewhat familiar with the mechanisms by which data are retrieved from a CD (I worked in CD mastering for three years before joining Stereophile), this was perplexing: I could think of no plausible explanation for a difference in sonic quality. As we shall see, the light reflected from a CD striking the photo-detector contains all the information encoded on the disc (footnote 1). Even if CD Stoplight could somehow affect the light striking the photo-detector, how could this change make the soundstage deeper? I was simultaneously disturbed and encouraged by this experience. Disturbed because it illustrates our fundamental lack of understanding of digital audio's mysteries, and encouraged by the promise that identification of previously unexplored phenomena could improve digital audio to the point where today's digital audio era will be regarded as the stone age.
These events prompted me to conduct a scientific examination of several CD "sonic cure-all" devices and treatments. I wanted to find an objective, measurable phenomenon that explains the undeniable musical differences heard by many listeners where, at least according to established digital audio theory, no differences should exist. For this inquiry, I measured several digital-domain performance criteria on untreated CDs, and then on the same CDs treated with various CD tweaks. The parameters measured include data error rates, ability to correct (rather than conceal) data errors, and jitter.
The six CD treatments and devices chosen for this experiment include three that allegedly affect optical phenomena and three that ostensibly affect the CD player's mechanical performance. The three optical treatments tested are CD Stoplight (the green paint), Finyl (a liquid applied to a disc surface, that, according to its promoters, provides "optical impedance matching"), and Armor All. The mechanical devices include CD Soundrings, The Mod Squad's CD Damper disc, and the Arcici LaserBase, a vibration-absorbing CD-player platform. I also measured playback signal jitter in a mid-priced CD player and the $4000 Esoteric P2 transport (regarded as having superb sonics). However, this is not intended as a survey of the musical benefits of these devices and treatments. In addition, I looked at the variation in quality of discs made at various CD manufacturing facilities around the world.
Another purpose of the article is to dispel some common misconceptions about CD error correction and its effect on sonic quality. If one believes the promoters of some of these CD treatments, errors are the single biggest source of sonic degradation in digital audio. In reality, errors are the least of CD's problems. However, this has not prevented marketeers from exploiting the audiophile's errorphobia in an attempt to sell products.
For example, Digital Systems and Solutions, Inc., manufacturer of Finyl, claim in their white paper that error concealment "results in a serious degrading of playback fidelity." They also state that errors can get through undetected, leading to a litany of sonic horrors including: "poor articulation of bass and mid-bass notes, attenuation of dynamics and smearing of transients, increased noise with loss of inner detail and intertransient silence, reduced midrange presence that diminishes clarity and transparency, loss of image specificity and focus, reduction of the apparent width and depth of soundstage—virtually eliminating the possibility of holophonic [sic] imagery, decreased resolution of the low level detail that is so necessary to the recovery of hall ambience, altered instrumental and vocal timbres that lack coherence or cohesiveness, obscuring of vocal textures and expression, instrumental lines and musical themes are more difficult to sort out, complex rhythms and tempos are less easily followed, the music will not be as emotionally involving and satisfying an experience as might have otherwise been possible, subtle breath effects on brass or wind instruments are more difficult to discern as are nuances of fingering and bowing on string instruments." This list, they concede, "is not claimed to be complete."
Technical background
Encoding and data retrieval: Before getting into the measurement results, let's arm ourselves with a little technical background on how the CD works.
A CD's surface is covered by a single spiral track of alternating "pit" and "land" formations. These structures, which encode binary data, are created during the laser mastering process. The CD master disc is a glass substrate coated with a very thin layer of photosensitive material. The glass master is rotated on a turntable while exposed to a laser beam that is modulated (turned on and off) by the digital data we wish to record on the disc. This creates a spiral of exposed and unexposed areas of the disc. When the master is later put under a chemical developing solution, areas of the photosensitive material exposed to the recording laser beam are etched away, creating a pit. Unexposed areas are unaffected by the developing solution and are called lands. These formations, which are among the smallest manufactured structures, are transferred through the manufacturing process to mass-produced discs. Fig.1 is a scanning electron microscope of a CD surface. Note that a human hair is about the width of 50 tracks.
The playback laser beam in the CD player is focused on these tiny pits and held on track by a servo system as the disc rotates. This beam is reflected from the disc to a photo-detector, a device that converts light into voltage. To distinguish between pit and land areas, the pit depth is one-quarter the wavelength of the playback laser beam. When laser light strikes a pit, a portion of the beam is reflected from the surrounding land, while some light is reflected from the pit bottom. Since the portion of light reflected from the pit bottom must travel a longer distance (1/4 wavelength down plus 1/4 wavelength back up), this portion of the beam is delayed by half a wavelength in relation to the beam reflected by the land. When these two beams combine, phase cancellation occurs, resulting in decreased output from the photo-detector. This variable-intensity beam thus contains all the information encoded on the disc.
Now that we understand how the playback beam/photo-detector can distinguish between pit and land, let's look at how these distinctions represent digital audio data. One may intuitively think that it would be logical for a pit to represent binary one and a land to represent binary zero, or vice versa. This method would certainly work, but a much more sophisticated scheme has been devised that is fundamental to the CD. It is called Eight-to-Fourteen Modulation, or EFM.
This encoding system elegantly solves a variety of data-retrieval functions. In EFM encoding, pit and land do not represent binary data directly. Instead, transitions from pit-to-land or land-to-pit represent binary one, while all other surfaces (land or pit bottom) represent binary zero. EFM encoding takes symbols of 8 bits and converts them into unique 14-bit words, creating a pattern in which binary ones are separated by a minimum of two zeros and a maximum of 10 zeros. The bit stream is thus given a specific pattern of ones and zeros that result in nine discrete pit or land lengths on the disc. The shortest pit or land length encodes three bits, while the longest encodes 11 bits. The blocks of 14 bits are linked by three "merging bits," resulting in an encoding ratio of 17:8. At first glance, it may seem odd that EFM encoding, in more than doubling the number of bits to be stored, can actually increase data density. But just this occurs: Storage density is increased by 25% over unmodulated encoding.
EFM has other inherent advantages. By inserting zeros between successive ones, the bandwidth of the signal reflected from the disc is decreased. The data rate from a CD is 4.3218 million bits per second (footnote 2), but the EFM signal has a bandwidth of only 720kHz. In addition, the EFM signal serves as a clock that, among other functions, controls the player's rotational servo.
The signal reflected from the disc is comprised of nine discrete frequencies, corresponding to the nine discrete pit or land lengths (footnote 3). The highest-frequency component, called "I3," is produced by the shortest pit or land length and has a frequency of 720kHz. This represents binary data 100. The lowest-frequency component, called "I11," is produced by the longest pit or land length and has a frequency of 193kHz. This represents binary data 10000000000. The signal reflected from the disc, produced by EFM encoding, is often called the HF (high frequency) signal. The varying periods of the sinewaves correspond to the periods of time required to read the various pit lengths.
At first impression, the HF signal appears to be analog, not one that carries digital data. However, the zero crossings of the waveforms contain the digital information encoded on the disc. Fig.2 shows the relationship between binary data, pit structure, and the recovered HF signal.
Fig.2 Relationship between binary data, pit structure, and the HF signal. (Reproduced from Principles of Digital Audio, Second Edition (1989), by Kenneth C. Pohlmann, with the permission of the publisher, Howard W. Sams & Company.)
HF signal quality is a direct function of pit shape, which in turn is affected by many factors during the CD manufacturing process. There is a direct correlation between error rates and pit shape. Poorly shaped pits result in a low-amplitude HF signal with poorly defined lines. Figs.3 and 4 show an excellent HF signal and a poor HF signal respectively.
CD data errors: Any digital storage medium is prone to data errors, and the CD is no exception. An error occurs when a binary one is mistakenly read as a binary zero (or vice versa), or when the data flow is momentarily interrupted. The latter, more common in CDs, is caused by manufacturing defects, surface scratches, and dirt or other foreign particles on the disc. Fortunately, the CD format incorporates extremely powerful error detection and correction codes that can completely correct a burst error of up to 4000 successive bits. The reconstructed data are identical to what was missing. This is called error correction. If the data loss exceeds the player's ability to correctly replace missing data, the player makes a best-guess estimate of the missing data and inserts this approximation into the data stream. This is called error concealment, or interpolation.
It is important to make the distinction between correction and concealment: correction is perfect and inaudible, while concealment has the potential for a momentary sonic degradation where the interpolation occurs.
A good general indication of disc quality (and the claimed error-reduction effects of some CD tweaks) is the Block Error Rate, or BLER. BLER is the number of blocks per second that contain errant data, before error correction. The raw data stream from a CD (called "channel bits") contains 7350 blocks per second, with a maximum allowable BLER (as specified by Philips) of 220. A disc with a BLER of 100 thus has 100 blocks out of 7350 with errant or missing data. In these experiments, Block Error Rate is the primary indicator of a particular tweak's effect on error-rate performance.
In addition to measuring the effects of CD tweaks on BLER, I explored their potential to reduce interpolations. To do this, I used the Pierre Verany test CD that has intentional dropouts in the spiral track. The disc has a sequence of tracks with increasingly long periods of missing data.
First, I found the track that was just above the threshold of producing an uncorrectable error (called an "E23 error") as analyzed by the Design Science CD Analyzer (see Sidebar). The track was played repeatedly to assure consistency, thus avoiding the ascription to chance of any subsequent change. Then, the same track was played and analyzed, this time after the addition of a CD treatment or device. This twofold approach—measuring a tweak's effect on both BLER and interpolations—would seem to cover the gamut of error-reduction potential.
There are two general misconceptions about CD errors and sound quality: 1) errors are the primary source of sonic degradation; and 2) if there are no uncorrectable errors, there can be no difference in sound.
The first conclusion is largely due to the marketing programs of CD-accessory manufacturers who claim their products reduce error rates. Many of the devices tested claim to improve sound quality by reducing the amount of error concealment performed by the CD player. In fact, interpolations (error concealment) rarely occur. In the unlikely event that concealment is performed, it will be momentary and thus have no effect on the overall sound. At worst, a transient tick or glitch would be audible.
To better understand the nature of data errors, a look at CD Read-Only Memory (CD-ROM) is useful. A CD-ROM is manufactured just like an audio CD, but contains computer data (text, graphics, application software, etc.) instead of music. The data retrieved from a CD-ROM must be absolutely accurate to the bit level, after error correction. If even a single wrong bit gets past the error correction, the entire program could crash. The errant bit may be within instructions for the host computer's microprocessor, causing the whole application to come to an instant halt, making the disc useless.
To prevent this, a quality-control procedure is routinely used at the mastering and pressing facility to assure 100% error-free performance. Samples of the finished CD-ROM are compared, bit for bit, to the original source data. For high-reliability applications, each replicated disc undergoes this process. This rigorous testing reveals much about the error-correction ability of the CD's Cross Interleaved Reed-Solomon encoding (CIRC). Throughout dozens of hours of this verification procedure, I cannot remember even a single instance of one wrong bit getting through.
It could be argued that CD-ROM has additional error-correction ability not found on CD audio discs. This is true, but the additional layer of error correction is almost never invoked. Furthermore, in all the hours of error-rate measuring for this project, I never encountered an E23 error, the first and most sensitive indication of an interpolation (except on the Pierre Verany disc, which has intentional errors). In fact, I saw only one E22 error, the last stage of correction before concealment. In retesting the disc, the E22 error disappeared, indicating it was probably due to a piece of dirt on the disc. Finally, the unlikely occurrence of an uncorrectable error is exemplified by the warning system in the Design Science CD Analyzer. The system beeps and changes the computer's display color to red to alert the operator if even an E22 error (fully corrected) is detected.
http://www.stereophile.com/reference/590jitter/
The Absolute Sound of What?
One of the things that distinguishes a dedicated audiophile from Joe Q. Public is that he has some notion of what audio fidelity is all about.
The typical buyer of a "steeryo" is seeking nothing more than pleasant or exciting sounds, and is easily satisfied because he has no greater expectation of audio than this. The audiophile, however, is aware that reproduced sound can resemble (more or less) real, live sound, and he is driven in a continual search for that ultimate truth ("fidelity to the original") even while realizing, intellectually at least, that it is unattainable.
Because he understands what the word "reproduction" means, the audiophile thinks in terms of a relationship to an original sound. This original is, of course, the sound of live music, and the touchstone for its reproduction is accuracy. Unfortunately, though, we don't really compare the reproduction with the real thing—because we can't. Only a recording engineer can saunter back and forth between the real thing (which takes place in a studio or hall) and the reproduction of it (in the control room with its monitor system). We audiophiles must be content to compare the reproduction with what we remember to be the sound of live music. Even the amateur recordist must carry the memory of that original sound home with his tapes in order to evaluate them.
And that memory may not serve us that well. Few of us have learned to listen with enough attention and skill to be able to break live sound down into its components and to observe what each sounds like. Most of us remember only an overall impression—the gestalt of the thing. And many of us must admit, to ourselves at least, that we have not heard live music for years or, worse, never at all. For the vast majority of audiophiles then, the reference standard is not the absolute sound of live music, but an imagined ideal—a mental picture of how we remember its having sounded or how we would like it to sound. At this point, accuracy becomes a dubious criterion because of the vagueness of the original to which we compare the copy. System evaluation becomes a (simple?) matter of "it's good if it sounds good."
The problem with this is that one man's good is another man's distortion. Different people listen to and assign different orders of importance to different aspects of reproduced sound. Thus, while two very picky listeners may agree that a system has good bass, good highs, and a colored middle range, they will disagree as to how good the system is if one happens to be critical of highs and lows while the other is critical of the middle range.
In short, we really don't have any way of reliably assessing the accuracy of reproduced sound. Even a recording engineer cannot be confident of the sound of his own recording, because what he hears in the control room depends on his monitoring equipment, which is no more—and is often less—accurate than a home system. (Many pros do not, in fact, aim for realism at all, but for what they call a "commercial sound"—one that will sell. Thus a recording may not even have the potential for sounding realistic.)
All this does not, however, discourage audiophiles in their search for the Holy Grail of musical accuracy. There are a couple of approaches from which to select. The casual audiophile, who has more interest in music than the ultimate in fi, will usually choose a record label whose releases he favors for their musical values, and will tailor his system to sound best with most of that label's recordings. Discs from other labels may sound good on this system too, but it will be a matter of luck, and bear little relationship to accuracy.
Perfectionist audiophiles, on the other hand, usually aim for maximum accuracy in the playback system itself. The idea here is that, if the system accurately reproduces what is on the recording, the best recordings will yield the most natural sound. (This philosophy has the added benefit of rewarding those record manufacturers who strive hardest for realism.)
This seems like an elegantly simple solution, but there's a flaw. In order to ascertain the accuracy of a disc's reproduction, we must have an original to compare it to. But we can't compare it to the sound that was fed into the master-tape recorder, because that sound was gone forever when the recording session ended. The closest we can get to that original signal is the one that comes from the recorder when the tape is played back. That, after all, is the signal that was used to cut the disc, and if the disc sounds the same as the tape, then we know our record-playing system (the arm, cartridge, and preamp) is accurate. Right? Not necessarily—the record cutting and pressing system was optimized based on a comparison to the original sound, but with probably a completely different phono system than the one you use at home.
Before approving a new release, a record producer is sent a test pressing of it (footnote 1), which he then plays through his reference system and compares with what he hears directly from the master tape. If they don't sound alike, he tells the cutting engineer to make appropriate equalization corrections for the final release cut, or to simply re-cut the disc with the same equalization.
Wouldn't this ensure that his disc sounds like the original tape? Not quite, because it is more than likely that his phono system and preamp have significant colorations, which will make the disc sound different from the way it "actually" sounds. Why, then, should our perfectionist record producer trust his playback system? Because he carefully chose it to make his records sound as much as possible like his tapes!
We've all heard of Catch 22, but in case you're unsure of its meaning, it is about circularity—in reasoning, causality, and Ultimate Truth. Circularity exists when A is a function of B, while B is determined by A. A popular example of circularity is the chicken-or-the-egg question. Then there's the apocryphal "Timbuktu Paradox," which relates the story of the retired sea captain who fires a cannon every day at the precise moment the town hall clock says 12 noon, while the town-hall custodian checks his clock every day by the sound of the 12 o'clock cannon.
What in fact does a record sound like? Think for a moment before answering. It has no sound at all. Hold one up to your ear, and what do you hear? Nothing, of course. To hear what's "on" a recording, you have to reproduce it through a phono system. And what does that phono system really sound like? It sounds like the record with various things added or subtracted. And the music goes 'round and 'round..
There really isn't any way of knowing precisely what is the sound of a record or its player. This is one reason why, in this age of high technology, audio continues to be such a cabalistic field. Where knowledge fails, mysticism moves in.
But just because we cannot make absolute assessments of disc-reproduction accuracy doesn't mean we should abandon the accuracy criterion altogether, any more than we should all stop trying to be good people just because we can't be perfect. There is, in fact, a way we can get reasonably close to the ultimate truth about an analog disc and its player, and that way believe it or not is through the Compact Disc.
The CD has all along been touted as an absolutely accurate recording/playback medium, no doubt to the embarrassment of those manufacturers who so promoted it. Even the mass circulation hi-fi magazines have been reporting that some players sound better than others, and that the best are getting better as time goes on. But another question that has assumed growing importance is just how good the Compact Disc system actually is, because the answer to that question will determine how far the CD can go towards needs of the audiophile who cares about accuracy (footnote 2).
Numbers of audiophile-oriented record manufacturers have been claiming that the CD sound is "virtually indistinguishable from" the sound of the original master tapes. Even allowing for a certain amount of hyperbole (footnote 3), this would seem to indicate that a CD may offer us the most direct path back to the sound of the original master recording. But how much does a CD sound like its master?
To my knowledge, the only investigation of this was done a couple of years ago by England's Hi-Fi News & Record Review. Those listening tests involved direct comparisons between the sound of some Decca CDs and their digital master tapes. The test results were not felt to be entirely conclusive. While there was agreement that the CDs sounded pretty much like the original masters, there was some disagreement as to how important were the minor differences noted.
HFN/RR's experiment is already outdated anyway. Since that time the audio quality of the best CD players has improved dramatically, while many of professional recorders have stayed the same. And the conditions of HFN/RR's tests were not quite the same as an analog disc/tape comparison, because a set of spurious electronics were introduced into the "original" signal: the digital recorder's playback circuitry.
When mastering from analog, the original signal—that is, the signal feeding the cutting system—is already in analog form and can be auditioned directly. But in CD mastering, the original is in digital form, and stays that way up until the time the disc is played in your home. In order to compare the original (digital) with the playback (analog), D/A conversion must occur at the output of the recording deck. And there's the catch. That D/A converter and audio section was not present in the chain that delivered the original signal to the CD. In other words, when we make a CD/master-tape comparison, the "original" sound is being processed by electronics which are different from those used for the CD playback, and the former may not be as good as the latter.
Professional recording equipment is notorious for having less than perfectionist-quality audio circuitry and parts. That's why every recording studio that aims for the best sound customizes its tape decks. Some consumer CD players, such as the Meridian and Mission units, probably produce a better sound from CD digital than do the decks used to master those CDs. So it is more than likely that, if HFN/RR were to repeat those tests today, the CD sound would emerge as the clearcut winner, and would actually be judged better than the "original tape."
Under the circumstances, though, it is likely that such comparisons between the master and the consumer product are more reliable for digital recordings than for analog ones, because there are no mechanical transducers involved. Bad electronics can do some nasty things to digital sound, but they tend to have relatively little effect on the spectral balance of the sound—the balance between bass and treble, and the absolute high-end content. Thus, while we may still quibble over other aspects of CD sound, there is little doubt but that what we hear from a CD is much closer in spectral balance to the master tape than what we hear from an analog reproduction of the same recording.
This is why I adopted CD as my "standard" for judging most aspects of the sound of analog signal sources. Where CDs contrast consistently with what I hear from analog, I assume (on faith, you might say) that the CD sound is closer to the truth in spectral balance and low-frequency quality. If that CD sound is not "good," I do not assume that the better analog sound is "right." Instead, I adjust the other components in my system—the loudspeakers, in particular—until the sound I hear from CD in the listening room is as close as possible to what I remember of live music. This then becomes my standard for evaluating analog sources. The sound I get from analog is of a very high standard, and it has very similar spectral balance to digital sources.
The CD is still not what I consider to be anything like an "absolute" standard, but I do believe it is the closest approach to such an absolute that we're likely to find. It's certainly better than wondering whether the lovely sounds I get from some analog discs are the result of almost-perfect everythings in the chain, or merely a fortuitous mating between gross system colorations all the way from the microphones to the loudspeakers.
http://www.stereophile.com/asweseeit/363/
The typical buyer of a "steeryo" is seeking nothing more than pleasant or exciting sounds, and is easily satisfied because he has no greater expectation of audio than this. The audiophile, however, is aware that reproduced sound can resemble (more or less) real, live sound, and he is driven in a continual search for that ultimate truth ("fidelity to the original") even while realizing, intellectually at least, that it is unattainable.
Because he understands what the word "reproduction" means, the audiophile thinks in terms of a relationship to an original sound. This original is, of course, the sound of live music, and the touchstone for its reproduction is accuracy. Unfortunately, though, we don't really compare the reproduction with the real thing—because we can't. Only a recording engineer can saunter back and forth between the real thing (which takes place in a studio or hall) and the reproduction of it (in the control room with its monitor system). We audiophiles must be content to compare the reproduction with what we remember to be the sound of live music. Even the amateur recordist must carry the memory of that original sound home with his tapes in order to evaluate them.
And that memory may not serve us that well. Few of us have learned to listen with enough attention and skill to be able to break live sound down into its components and to observe what each sounds like. Most of us remember only an overall impression—the gestalt of the thing. And many of us must admit, to ourselves at least, that we have not heard live music for years or, worse, never at all. For the vast majority of audiophiles then, the reference standard is not the absolute sound of live music, but an imagined ideal—a mental picture of how we remember its having sounded or how we would like it to sound. At this point, accuracy becomes a dubious criterion because of the vagueness of the original to which we compare the copy. System evaluation becomes a (simple?) matter of "it's good if it sounds good."
The problem with this is that one man's good is another man's distortion. Different people listen to and assign different orders of importance to different aspects of reproduced sound. Thus, while two very picky listeners may agree that a system has good bass, good highs, and a colored middle range, they will disagree as to how good the system is if one happens to be critical of highs and lows while the other is critical of the middle range.
In short, we really don't have any way of reliably assessing the accuracy of reproduced sound. Even a recording engineer cannot be confident of the sound of his own recording, because what he hears in the control room depends on his monitoring equipment, which is no more—and is often less—accurate than a home system. (Many pros do not, in fact, aim for realism at all, but for what they call a "commercial sound"—one that will sell. Thus a recording may not even have the potential for sounding realistic.)
All this does not, however, discourage audiophiles in their search for the Holy Grail of musical accuracy. There are a couple of approaches from which to select. The casual audiophile, who has more interest in music than the ultimate in fi, will usually choose a record label whose releases he favors for their musical values, and will tailor his system to sound best with most of that label's recordings. Discs from other labels may sound good on this system too, but it will be a matter of luck, and bear little relationship to accuracy.
Perfectionist audiophiles, on the other hand, usually aim for maximum accuracy in the playback system itself. The idea here is that, if the system accurately reproduces what is on the recording, the best recordings will yield the most natural sound. (This philosophy has the added benefit of rewarding those record manufacturers who strive hardest for realism.)
This seems like an elegantly simple solution, but there's a flaw. In order to ascertain the accuracy of a disc's reproduction, we must have an original to compare it to. But we can't compare it to the sound that was fed into the master-tape recorder, because that sound was gone forever when the recording session ended. The closest we can get to that original signal is the one that comes from the recorder when the tape is played back. That, after all, is the signal that was used to cut the disc, and if the disc sounds the same as the tape, then we know our record-playing system (the arm, cartridge, and preamp) is accurate. Right? Not necessarily—the record cutting and pressing system was optimized based on a comparison to the original sound, but with probably a completely different phono system than the one you use at home.
Before approving a new release, a record producer is sent a test pressing of it (footnote 1), which he then plays through his reference system and compares with what he hears directly from the master tape. If they don't sound alike, he tells the cutting engineer to make appropriate equalization corrections for the final release cut, or to simply re-cut the disc with the same equalization.
Wouldn't this ensure that his disc sounds like the original tape? Not quite, because it is more than likely that his phono system and preamp have significant colorations, which will make the disc sound different from the way it "actually" sounds. Why, then, should our perfectionist record producer trust his playback system? Because he carefully chose it to make his records sound as much as possible like his tapes!
We've all heard of Catch 22, but in case you're unsure of its meaning, it is about circularity—in reasoning, causality, and Ultimate Truth. Circularity exists when A is a function of B, while B is determined by A. A popular example of circularity is the chicken-or-the-egg question. Then there's the apocryphal "Timbuktu Paradox," which relates the story of the retired sea captain who fires a cannon every day at the precise moment the town hall clock says 12 noon, while the town-hall custodian checks his clock every day by the sound of the 12 o'clock cannon.
What in fact does a record sound like? Think for a moment before answering. It has no sound at all. Hold one up to your ear, and what do you hear? Nothing, of course. To hear what's "on" a recording, you have to reproduce it through a phono system. And what does that phono system really sound like? It sounds like the record with various things added or subtracted. And the music goes 'round and 'round..
There really isn't any way of knowing precisely what is the sound of a record or its player. This is one reason why, in this age of high technology, audio continues to be such a cabalistic field. Where knowledge fails, mysticism moves in.
But just because we cannot make absolute assessments of disc-reproduction accuracy doesn't mean we should abandon the accuracy criterion altogether, any more than we should all stop trying to be good people just because we can't be perfect. There is, in fact, a way we can get reasonably close to the ultimate truth about an analog disc and its player, and that way believe it or not is through the Compact Disc.
The CD has all along been touted as an absolutely accurate recording/playback medium, no doubt to the embarrassment of those manufacturers who so promoted it. Even the mass circulation hi-fi magazines have been reporting that some players sound better than others, and that the best are getting better as time goes on. But another question that has assumed growing importance is just how good the Compact Disc system actually is, because the answer to that question will determine how far the CD can go towards needs of the audiophile who cares about accuracy (footnote 2).
Numbers of audiophile-oriented record manufacturers have been claiming that the CD sound is "virtually indistinguishable from" the sound of the original master tapes. Even allowing for a certain amount of hyperbole (footnote 3), this would seem to indicate that a CD may offer us the most direct path back to the sound of the original master recording. But how much does a CD sound like its master?
To my knowledge, the only investigation of this was done a couple of years ago by England's Hi-Fi News & Record Review. Those listening tests involved direct comparisons between the sound of some Decca CDs and their digital master tapes. The test results were not felt to be entirely conclusive. While there was agreement that the CDs sounded pretty much like the original masters, there was some disagreement as to how important were the minor differences noted.
HFN/RR's experiment is already outdated anyway. Since that time the audio quality of the best CD players has improved dramatically, while many of professional recorders have stayed the same. And the conditions of HFN/RR's tests were not quite the same as an analog disc/tape comparison, because a set of spurious electronics were introduced into the "original" signal: the digital recorder's playback circuitry.
When mastering from analog, the original signal—that is, the signal feeding the cutting system—is already in analog form and can be auditioned directly. But in CD mastering, the original is in digital form, and stays that way up until the time the disc is played in your home. In order to compare the original (digital) with the playback (analog), D/A conversion must occur at the output of the recording deck. And there's the catch. That D/A converter and audio section was not present in the chain that delivered the original signal to the CD. In other words, when we make a CD/master-tape comparison, the "original" sound is being processed by electronics which are different from those used for the CD playback, and the former may not be as good as the latter.
Professional recording equipment is notorious for having less than perfectionist-quality audio circuitry and parts. That's why every recording studio that aims for the best sound customizes its tape decks. Some consumer CD players, such as the Meridian and Mission units, probably produce a better sound from CD digital than do the decks used to master those CDs. So it is more than likely that, if HFN/RR were to repeat those tests today, the CD sound would emerge as the clearcut winner, and would actually be judged better than the "original tape."
Under the circumstances, though, it is likely that such comparisons between the master and the consumer product are more reliable for digital recordings than for analog ones, because there are no mechanical transducers involved. Bad electronics can do some nasty things to digital sound, but they tend to have relatively little effect on the spectral balance of the sound—the balance between bass and treble, and the absolute high-end content. Thus, while we may still quibble over other aspects of CD sound, there is little doubt but that what we hear from a CD is much closer in spectral balance to the master tape than what we hear from an analog reproduction of the same recording.
This is why I adopted CD as my "standard" for judging most aspects of the sound of analog signal sources. Where CDs contrast consistently with what I hear from analog, I assume (on faith, you might say) that the CD sound is closer to the truth in spectral balance and low-frequency quality. If that CD sound is not "good," I do not assume that the better analog sound is "right." Instead, I adjust the other components in my system—the loudspeakers, in particular—until the sound I hear from CD in the listening room is as close as possible to what I remember of live music. This then becomes my standard for evaluating analog sources. The sound I get from analog is of a very high standard, and it has very similar spectral balance to digital sources.
The CD is still not what I consider to be anything like an "absolute" standard, but I do believe it is the closest approach to such an absolute that we're likely to find. It's certainly better than wondering whether the lovely sounds I get from some analog discs are the result of almost-perfect everythings in the chain, or merely a fortuitous mating between gross system colorations all the way from the microphones to the loudspeakers.
http://www.stereophile.com/asweseeit/363/
Tuesday, May 29, 2007
The Sights and Sounds of Vista
Newsletter #18: Microsoft Remakes Multimedia
When we say Microsoft Vista has some glitz, it's not just marketing; the newest version of Windows sports some revamped video and audio functions designed to promote the digital arts.
We got a hint of the new multimedia even before Vista shipped, as the updated Windows Media Player, and that first look offers a good introduction.
Learn the New Tune
What's new in Windows Media Center?
It has the same basic features as before, but it sports a redesigned menu system, mainly so you can control it from an Xbox 360 over your home network.
Has Windows Media Player changed?
A new interface gives you additional ways to organize and browse your media collection.
For example, you can access your music by an album cover view. Vista's search feature is integrated into Windows Media Player, so you can find media more easily, too. And Windows Media Player includes tie-ins to URGE, a for-pay music service that Microsoft launched with MTV.
Hardware Concerns
Will Vista play HD-DVDs and Blu-ray discs?
Not without third-party software. Though Vista ships with the infrastructure necessary to support HD-DVD--drivers, file system, codecs, and other components--you'll need additional dedicated software to play an HD-DVD video, and the OS has no native support for Blu-ray Disc.
Because of Digital Rights Management for prerecorded high-definition media, will I need to buy a new monitor to play premium high-def content?
You might, regardless of whether you're running Vista or Windows XP. For a PC to send next-generation video content to a display, the display must support HDCP--and while most HDTVs do support this copy-protection technology, many older monitors that support high-def resolutions do not.
http://www.ecoustics.com/pcw/howto/131951
When we say Microsoft Vista has some glitz, it's not just marketing; the newest version of Windows sports some revamped video and audio functions designed to promote the digital arts.
We got a hint of the new multimedia even before Vista shipped, as the updated Windows Media Player, and that first look offers a good introduction.
Learn the New Tune
What's new in Windows Media Center?
It has the same basic features as before, but it sports a redesigned menu system, mainly so you can control it from an Xbox 360 over your home network.
Has Windows Media Player changed?
A new interface gives you additional ways to organize and browse your media collection.
For example, you can access your music by an album cover view. Vista's search feature is integrated into Windows Media Player, so you can find media more easily, too. And Windows Media Player includes tie-ins to URGE, a for-pay music service that Microsoft launched with MTV.
Hardware Concerns
Will Vista play HD-DVDs and Blu-ray discs?
Not without third-party software. Though Vista ships with the infrastructure necessary to support HD-DVD--drivers, file system, codecs, and other components--you'll need additional dedicated software to play an HD-DVD video, and the OS has no native support for Blu-ray Disc.
Because of Digital Rights Management for prerecorded high-definition media, will I need to buy a new monitor to play premium high-def content?
You might, regardless of whether you're running Vista or Windows XP. For a PC to send next-generation video content to a display, the display must support HDCP--and while most HDTVs do support this copy-protection technology, many older monitors that support high-def resolutions do not.
http://www.ecoustics.com/pcw/howto/131951
Do-It-Yourself Surveillance Protects Home or Business
Is that summer downpour flooding your basement? Did Rover get into the garbage again? Is your 50-inch flat-panel TV still in place? Find out from anywhere by using your PC to create an affordable home surveillance system that you can access over the Internet, or even over your cell phone. A professionally installed surveillance system costs at least $2000, but you can set up an uncomplicated USB-connected Webcam such as Logitech's QuickCam Chat for $30, a wireless camera that can be placed almost anywhere for less than $200, or a complete PC-based monitoring system for under $1000.
A basic surveillance system requires three things: a camera; motion-sensing software to activate the camera and to store its video or still images; and software to send the images over the Internet. Adding a wired or wireless network expands your home-surveillance capabilities.
If you're on a tight budget or you don't want to deal with installing remote cameras, an inexpensive Webcam can serve as a bare-bones surveillance device. Many Webcams come with motion-sensing and remote-access software, but paying extra for a full-featured program may be worthwhile, especially if you want to use several Webcams of different makes (for two software recommendations, see " Cameras With Swivel").
The biggest drawback of a Webcam, of course, is that it's tethered by a USB cable to your PC. Powered USB hubs and USB active repeater cables allow you to double or triple USB's 5-meter length limit. Or you can wait for the convenience of wireless USB products, which should arrive soon. In fact, Belkin's CableFree wireless USB hub may be available by the time you read this.
Click to see a full-size image.
IP cameras, on the other hand, can be placed anywhere there's a network connection, making them ideal for homes or offices that already have a wireless network. Since they connect directly to your router rather than through your PC, you don't need to keep the machine on to view the camera's image in a browser. Prices for cameras with such features as night vision, remote-control positioning (pan-and-tilt controls, for instance), and zoom lenses can quickly escalate past $1000, but less expensive wireless cameras like D-Link's DCS-5300G (about $500 online), Linksys's Compact Wireless G Internet Video Camera (about $100 online) and 4XEM's WLPTG Wireless Pan/Tilt IP Network Camera (about $390 online) have many of these extra features.
The pan-and-tilt capability of the 4XEM and D-Link units let me monitor my living room, kitchen, and yard (through a window) with one camera whose view I controlled remotely, rather than having to use two or three stationary cameras. If you have pets, attach a speaker to let them hear your voice from afar.
I installed three different wireless cameras on my wireless network, and though I struggled with the setup, after 5 hours I was monitoring my dog's water bowl, my front door, and my vegetable garden from my cousin's house across town.
Of course, your network camera will only be as useful as the surveillance software that runs it. If the software bundled with your camera is difficult to use, has too limited a set of features, or is impossible to install, you can ditch it and try one of the many third-party alternatives, such as DeskShare's $50 WebCam Monitor or iCode's $79 i-Catcher Sentry. I found both apps much easier to configure and more useful than the programs that came with several of the cameras I tried out.
Before you buy a camera-controller app, make sure its codec works with your cameras. IP cameras typically support either the MJPEG or the MPEG-4 codec, though some newer cameras support both. MPEG-4 cameras produce smaller video files, but at lower resolutions than MJPEG.
Here answers to some common questions about remote surveillance cameras.
How do I power a remote camera? If you want to place a camera somewhere without easy access to an electrical outlet, look for a camera that supports Power over Ethernet (PoE). PoE cameras can draw power from the CAT5 ethernet cable used to transmit data, eliminating the need for a separate power line. Some cameras feature built-in PoE support, while others, such as D-Link's $45 DWL-P200, require a PoE adapter.
What else can I monitor? If you need more than audio or visual confirmation that your home or business is safe and sound, Digi's Watchport Sensors monitor temperature, moisture, and motion. Each sensor connects via USB to a PC and comes with software that sends alerts via e-mail or cell phone. The sensors cost between $130 and $180 online.
Alternatively, Motorola's Homesight Wireless Easy Starter Kit HMEZ2000 monitoring system offers a turnkey home security system with modules for wireless cameras, window and door monitors, and wireless (but not Wi-Fi) temperature and moisture sensors. The starter kit costs about $250. Water, temperature, and window/door sensors cost between $40 and $80 each.
Where do I go for help? Don't waste too much time with a troublesome installation. Call tech support; 4XEM's excellent support line made my setup a breeze, while an hour with a D-Link support tech convinced me to try WebCam Monitor instead of sticking with D-Link's software. My most important lesson: If one quick call to tech support doesn't solve your problem, return your camera for one from a different manufacturer.
Setting up an external link to the Internet can be challenging on any camera. Check out the overview at networkcamerareviews.com and find several useful tips for installing and running an IP camera.
If you print something every day, you probably waste a little something every day as well. TheGreenPrint utility lets you cut down on wasted paper and ink by making it fast and easy to identify and delete unwanted pages, text, or graphics in print jobs. GreenPrint installs as a printer, so if you designate it as your default, it automatically pops up each time you print. At $35 (with a free 14-day trial), the program certainly isn't cheap--but given the price of ink and paper, it can pay for itself pretty quickly.
http://www.ecoustics.com/pcw/howto/131813
A basic surveillance system requires three things: a camera; motion-sensing software to activate the camera and to store its video or still images; and software to send the images over the Internet. Adding a wired or wireless network expands your home-surveillance capabilities.
If you're on a tight budget or you don't want to deal with installing remote cameras, an inexpensive Webcam can serve as a bare-bones surveillance device. Many Webcams come with motion-sensing and remote-access software, but paying extra for a full-featured program may be worthwhile, especially if you want to use several Webcams of different makes (for two software recommendations, see " Cameras With Swivel").
The biggest drawback of a Webcam, of course, is that it's tethered by a USB cable to your PC. Powered USB hubs and USB active repeater cables allow you to double or triple USB's 5-meter length limit. Or you can wait for the convenience of wireless USB products, which should arrive soon. In fact, Belkin's CableFree wireless USB hub may be available by the time you read this.
Click to see a full-size image.
IP cameras, on the other hand, can be placed anywhere there's a network connection, making them ideal for homes or offices that already have a wireless network. Since they connect directly to your router rather than through your PC, you don't need to keep the machine on to view the camera's image in a browser. Prices for cameras with such features as night vision, remote-control positioning (pan-and-tilt controls, for instance), and zoom lenses can quickly escalate past $1000, but less expensive wireless cameras like D-Link's DCS-5300G (about $500 online), Linksys's Compact Wireless G Internet Video Camera (about $100 online) and 4XEM's WLPTG Wireless Pan/Tilt IP Network Camera (about $390 online) have many of these extra features.
The pan-and-tilt capability of the 4XEM and D-Link units let me monitor my living room, kitchen, and yard (through a window) with one camera whose view I controlled remotely, rather than having to use two or three stationary cameras. If you have pets, attach a speaker to let them hear your voice from afar.
I installed three different wireless cameras on my wireless network, and though I struggled with the setup, after 5 hours I was monitoring my dog's water bowl, my front door, and my vegetable garden from my cousin's house across town.
Of course, your network camera will only be as useful as the surveillance software that runs it. If the software bundled with your camera is difficult to use, has too limited a set of features, or is impossible to install, you can ditch it and try one of the many third-party alternatives, such as DeskShare's $50 WebCam Monitor or iCode's $79 i-Catcher Sentry. I found both apps much easier to configure and more useful than the programs that came with several of the cameras I tried out.
Before you buy a camera-controller app, make sure its codec works with your cameras. IP cameras typically support either the MJPEG or the MPEG-4 codec, though some newer cameras support both. MPEG-4 cameras produce smaller video files, but at lower resolutions than MJPEG.
Here answers to some common questions about remote surveillance cameras.
How do I power a remote camera? If you want to place a camera somewhere without easy access to an electrical outlet, look for a camera that supports Power over Ethernet (PoE). PoE cameras can draw power from the CAT5 ethernet cable used to transmit data, eliminating the need for a separate power line. Some cameras feature built-in PoE support, while others, such as D-Link's $45 DWL-P200, require a PoE adapter.
What else can I monitor? If you need more than audio or visual confirmation that your home or business is safe and sound, Digi's Watchport Sensors monitor temperature, moisture, and motion. Each sensor connects via USB to a PC and comes with software that sends alerts via e-mail or cell phone. The sensors cost between $130 and $180 online.
Alternatively, Motorola's Homesight Wireless Easy Starter Kit HMEZ2000 monitoring system offers a turnkey home security system with modules for wireless cameras, window and door monitors, and wireless (but not Wi-Fi) temperature and moisture sensors. The starter kit costs about $250. Water, temperature, and window/door sensors cost between $40 and $80 each.
Where do I go for help? Don't waste too much time with a troublesome installation. Call tech support; 4XEM's excellent support line made my setup a breeze, while an hour with a D-Link support tech convinced me to try WebCam Monitor instead of sticking with D-Link's software. My most important lesson: If one quick call to tech support doesn't solve your problem, return your camera for one from a different manufacturer.
Setting up an external link to the Internet can be challenging on any camera. Check out the overview at networkcamerareviews.com and find several useful tips for installing and running an IP camera.
If you print something every day, you probably waste a little something every day as well. TheGreenPrint utility lets you cut down on wasted paper and ink by making it fast and easy to identify and delete unwanted pages, text, or graphics in print jobs. GreenPrint installs as a printer, so if you designate it as your default, it automatically pops up each time you print. At $35 (with a free 14-day trial), the program certainly isn't cheap--but given the price of ink and paper, it can pay for itself pretty quickly.
http://www.ecoustics.com/pcw/howto/131813
Ten Things You Need to Know About 1080p
New models of consumer electronics products almost change with the seasons: you've finally understood why you need a High Definition Television (HDTV) when along comes yet another electronic upgrade. As exciting as these developments are, they may also provoke vague feelings of discontent. This can occur if some know-it-all points out that your HD display is only 720p. When this happened to me recently, I countered with the fact that I was viewing HDTV while this person was still in nursery school. (Japan developed an analog version of HDTV in the 1980s, which I saw on press trips to Japan and later viewed in Canada when TV broadcasters there considered adopting the Japanese HDTV system for the future needs of Canadian TV broadcasting. It was ultimately rejected.)
hdtv
As many readers are aware, the "1080p" tide has been rising for at least a year and this spring it seems to have reached a new high-water mark, in part stimulated by the market appearance of new high-definition DVD players: HD-DVD and Blu-ray, recorded and studio mastered in 1080p. These two formats are not compatible (except for LG's HD-DVD/Blu-ray combo player, and a new combo unit due from Samsung), however they will play your existing DVDs.
Resisting the marketing juggernaut is never easy (we really know how to consume in the 21st century) so in the spirit of both welcoming and explaining 1080p, here are some guidelines to help you navigate the claims and counter claims:
1. What is it? "1080p" stands for 1080 progressive. It means that a video display or video source has the capability to display a high-definition video image made up of 1080 horizontal "lines" progressively scanned from the top to the bottom of the screen. Your old analog CRT set yielded about 330 lines. A standard DVD player delivers 480 lines. In techie terms, a 1080p high-definition set will display an image comprised of 1920 x 1080 pixels, or approximately 2 million pixels (a pixel is a picture element) versus a 720p image, which consists of 1280 x 720 pixels, or about 921,600 pixels. Other things being equal, the more pixels there are in an image, the greater the potential detail and clarity.
"1080p" is a refinement of HD video technology that has evolved from earlier HD displays known as 720p or 1080i (i for interlaced). The latter (720p or 1080i) are the existing standards for HD images broadcast over the air or by cable or satellite. Broadcast 1080p images are not available -- yet. But they may be some years down the road.
2. If you own or buy a new 1080p set, it will convert or upscale incoming 720p or 1080i images to 1080p. The upscaled images may look smoother and more nuanced, clearer if you will, than those viewed on a 720p set.
3. If you already own an HD set that is several years old, it will likely be a 720p model (rarely 1080i unless it's a CRT HD set), so there is no point in getting video sources that deliver a 1080p image because your video device can't display the extra pixels, unless of course you decide to replace your 720p or 1080i HDTV with a 1080p HDTV.
4. If you are deliberating about buying a new 1080p large screen display, then it will let you do two things: either sit closer to the screen than you otherwise could if you had a 720p display, or, if you decide to go for a 1080p front projector, then you could project a considerably bigger screen image that would look as clear and sharp as a 720p image viewed from twice as far back.
For very large TV displays -- 65 inches diagonal, say, or projected images of 96 or 108 inches, you would see more detail from viewing distances of 5, 8, or 9 feet, respectively. Note that 9 feet is currently the average viewing distance for TV in most homes. On the other hand, because a 1080p set has almost twice as many pixels as a 720p display, subtleties and gradations of color and texture should be better, and visible.
5. Some new AV receivers and DVD players have built-in video up-conversion and scaling to 1080p. The upconversion to 1080p done in an AV receiver is only a convenience, and may not be executed as well as the conversion performed internally in your 1080p video display or projector.
6. Note that any 1080p display or 1080p projector will, on its own, upconvert any incoming standard or high-definition video source connected to it to 1080p. You do not need to purchase an outboard scaler in an AV receiver to perform that function. Your 1080p set will do that automatically because it must in order to display the image and fill all the pixels. (Techies call the latter the set’s "native resolution" -- 1080p.)
7. You should also note that upconversion (scaling) to 1080p of standard definition (SD) video sources like regular DVDs or standard TV broadcasts will not make them look like a true HD image (720p or 1080i). They may appear smoother to the eye, but detail cannot be added by up-conversion.
8. The only sources currently available for true 1080p images are HD-DVD and Blu-ray discs, and those must be delivered from an HD-DVD or Blu-ray disc player via HDMI cables. HDMI connections carry video images as well as standard images -- and 1080p -- in digital form, whereas component video cables are analog and carry 720p or 1080i HD images. While component video cables are technically able to pass 1080p images, Hollywood studios do not permit 1080p discs to be made without the anti-piracy digital handshake code that must be passed via HDMI cables. HD-DVD or Blu-ray players will only output 1080p signals over HDMI connections.
9. Finally, if you use a 50-inch to 60-inch diagonal HD display, and plan on sitting farther than 10 feet away from it, the 1080p display may not look any clearer than a 720p display would at that distance, however you may perceive a slightly smoother and more satisfying picture from the 1080p set. Still, we are talking subtleties here. Only if you sit 5 feet or so from a 60-inch 1080p screen will the increased clarity of 1080p be immediately apparent.
10. If you are about to purchase an HD set, then getting a 1080p display will "future-proof" your system because it will display the maximum picture resolution from HD-DVD or Blu-ray discs no matter which format "wins", and it will be capable of displaying the highest clarity possible for almost any new video delivery system coming down the pipe. Of course, as we discussed earlier, there is always something else on the horizon, including the huge palette of colors obtainable with Deep Color, which new 1080p sets will be able to access through the latest version of HDMI 1.3 connections this fall.
http://forum.ecoustics.com/bbs/messages/34579/356979.html
hdtv
As many readers are aware, the "1080p" tide has been rising for at least a year and this spring it seems to have reached a new high-water mark, in part stimulated by the market appearance of new high-definition DVD players: HD-DVD and Blu-ray, recorded and studio mastered in 1080p. These two formats are not compatible (except for LG's HD-DVD/Blu-ray combo player, and a new combo unit due from Samsung), however they will play your existing DVDs.
Resisting the marketing juggernaut is never easy (we really know how to consume in the 21st century) so in the spirit of both welcoming and explaining 1080p, here are some guidelines to help you navigate the claims and counter claims:
1. What is it? "1080p" stands for 1080 progressive. It means that a video display or video source has the capability to display a high-definition video image made up of 1080 horizontal "lines" progressively scanned from the top to the bottom of the screen. Your old analog CRT set yielded about 330 lines. A standard DVD player delivers 480 lines. In techie terms, a 1080p high-definition set will display an image comprised of 1920 x 1080 pixels, or approximately 2 million pixels (a pixel is a picture element) versus a 720p image, which consists of 1280 x 720 pixels, or about 921,600 pixels. Other things being equal, the more pixels there are in an image, the greater the potential detail and clarity.
"1080p" is a refinement of HD video technology that has evolved from earlier HD displays known as 720p or 1080i (i for interlaced). The latter (720p or 1080i) are the existing standards for HD images broadcast over the air or by cable or satellite. Broadcast 1080p images are not available -- yet. But they may be some years down the road.
2. If you own or buy a new 1080p set, it will convert or upscale incoming 720p or 1080i images to 1080p. The upscaled images may look smoother and more nuanced, clearer if you will, than those viewed on a 720p set.
3. If you already own an HD set that is several years old, it will likely be a 720p model (rarely 1080i unless it's a CRT HD set), so there is no point in getting video sources that deliver a 1080p image because your video device can't display the extra pixels, unless of course you decide to replace your 720p or 1080i HDTV with a 1080p HDTV.
4. If you are deliberating about buying a new 1080p large screen display, then it will let you do two things: either sit closer to the screen than you otherwise could if you had a 720p display, or, if you decide to go for a 1080p front projector, then you could project a considerably bigger screen image that would look as clear and sharp as a 720p image viewed from twice as far back.
For very large TV displays -- 65 inches diagonal, say, or projected images of 96 or 108 inches, you would see more detail from viewing distances of 5, 8, or 9 feet, respectively. Note that 9 feet is currently the average viewing distance for TV in most homes. On the other hand, because a 1080p set has almost twice as many pixels as a 720p display, subtleties and gradations of color and texture should be better, and visible.
5. Some new AV receivers and DVD players have built-in video up-conversion and scaling to 1080p. The upconversion to 1080p done in an AV receiver is only a convenience, and may not be executed as well as the conversion performed internally in your 1080p video display or projector.
6. Note that any 1080p display or 1080p projector will, on its own, upconvert any incoming standard or high-definition video source connected to it to 1080p. You do not need to purchase an outboard scaler in an AV receiver to perform that function. Your 1080p set will do that automatically because it must in order to display the image and fill all the pixels. (Techies call the latter the set’s "native resolution" -- 1080p.)
7. You should also note that upconversion (scaling) to 1080p of standard definition (SD) video sources like regular DVDs or standard TV broadcasts will not make them look like a true HD image (720p or 1080i). They may appear smoother to the eye, but detail cannot be added by up-conversion.
8. The only sources currently available for true 1080p images are HD-DVD and Blu-ray discs, and those must be delivered from an HD-DVD or Blu-ray disc player via HDMI cables. HDMI connections carry video images as well as standard images -- and 1080p -- in digital form, whereas component video cables are analog and carry 720p or 1080i HD images. While component video cables are technically able to pass 1080p images, Hollywood studios do not permit 1080p discs to be made without the anti-piracy digital handshake code that must be passed via HDMI cables. HD-DVD or Blu-ray players will only output 1080p signals over HDMI connections.
9. Finally, if you use a 50-inch to 60-inch diagonal HD display, and plan on sitting farther than 10 feet away from it, the 1080p display may not look any clearer than a 720p display would at that distance, however you may perceive a slightly smoother and more satisfying picture from the 1080p set. Still, we are talking subtleties here. Only if you sit 5 feet or so from a 60-inch 1080p screen will the increased clarity of 1080p be immediately apparent.
10. If you are about to purchase an HD set, then getting a 1080p display will "future-proof" your system because it will display the maximum picture resolution from HD-DVD or Blu-ray discs no matter which format "wins", and it will be capable of displaying the highest clarity possible for almost any new video delivery system coming down the pipe. Of course, as we discussed earlier, there is always something else on the horizon, including the huge palette of colors obtainable with Deep Color, which new 1080p sets will be able to access through the latest version of HDMI 1.3 connections this fall.
http://forum.ecoustics.com/bbs/messages/34579/356979.html
Stunning Photos With High Dynamic Range, Part 2
Use specialized software to combine images for a great effect.
If you've ever photographed an idyllic landscape and ended up with a washed-out sky and dark, underexposed blobs instead of shadows, you'll understand why photographers are falling in love with High Dynamic Range photography. HDR allows you to capture far more color, brightness, and contrast information in photos than has been possible.
Last week we talked about how to capture the series of photos that would become part of our HDR masterpiece.
Combining the Images
Shooting the series was half the battle; now it's time to combine the photos into a single image that takes all the best parts of each.
You've got a wide choice of programs to create HDR photos. Adobe Photoshop CS2, for example, has an HDR feature. So does Ulead PhotoImpact. There are also some stand-alone HDR utilities out there, like Photogenics HDR and Photomatix Pro.
I downloaded the free trial version of Photomatix Pro. There's no time limit on how long you can use the trial version, but it inscribes a watermark across each of your photos unless you pay $99 for the license.
Using Photomatix Pro
To use the program, drag your set of bracketed photos into the program window and wait for them to display. If you haven't made any HDR photos of your own yet, here are some sample source images you can use (I took these photos on a tripod in front of my house near dusk):
Choose HDR, Generate from the menu and click OK when the program asks if you want to use the open images.
In the next dialog box, select the check box to align the source images--this lines up your photos in case you were handholding the camera or the tripod moved a bit between shots--and choose the default "standard tone curve." Click OK.
After some processing time, you'll get a result. It probably won't look very good, but don't worry: The composite image holds more contrast information than a typical computer display is capable of showing. The final step is to optimize the image for the screen. Choose HDR, Tone Mapping from the menu.
On this final screen, you can tweak many aspects of the photo, such as the white and black levels, the color saturation, and contrast levels. Feel free to experiment with the settings.
Click for full image.
You'll probably find that often you can just click OK to accept the defaults; the results will look impressive without much tweaking. I used a series of five photos for my HDR image, which appears on the right.
HDR isn't perfect. Because it relies on a series of photos, it's not appropriate for action photography--or, in fact, photos in which pretty much anything moves at all. It requires meticulous setup, a tripod, enough patience to configure a series of bracketed images--and, of course, the software to glue it all together at the end. But if you can deal with those shortcomings, you can make some photos that are nothing short of stunning.
Hot Pic of the Week
Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.
Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.
Click for full image.
This Week's Hot Pic: "Summer Snack," by Patrick Marcigliano, Cumming, Georgia
Patrick says: "I took this shot of my daughter at a beach house after she had just come in from the beach to eat some lunch. She was hopping up and down at the table's edge, playing hide and seek with me. I just happened to catch her when she paused for just a second to see what I would do."
http://www.ecoustics.com/pcw/howto/131612
If you've ever photographed an idyllic landscape and ended up with a washed-out sky and dark, underexposed blobs instead of shadows, you'll understand why photographers are falling in love with High Dynamic Range photography. HDR allows you to capture far more color, brightness, and contrast information in photos than has been possible.
Last week we talked about how to capture the series of photos that would become part of our HDR masterpiece.
Combining the Images
Shooting the series was half the battle; now it's time to combine the photos into a single image that takes all the best parts of each.
You've got a wide choice of programs to create HDR photos. Adobe Photoshop CS2, for example, has an HDR feature. So does Ulead PhotoImpact. There are also some stand-alone HDR utilities out there, like Photogenics HDR and Photomatix Pro.
I downloaded the free trial version of Photomatix Pro. There's no time limit on how long you can use the trial version, but it inscribes a watermark across each of your photos unless you pay $99 for the license.
Using Photomatix Pro
To use the program, drag your set of bracketed photos into the program window and wait for them to display. If you haven't made any HDR photos of your own yet, here are some sample source images you can use (I took these photos on a tripod in front of my house near dusk):
Choose HDR, Generate from the menu and click OK when the program asks if you want to use the open images.
In the next dialog box, select the check box to align the source images--this lines up your photos in case you were handholding the camera or the tripod moved a bit between shots--and choose the default "standard tone curve." Click OK.
After some processing time, you'll get a result. It probably won't look very good, but don't worry: The composite image holds more contrast information than a typical computer display is capable of showing. The final step is to optimize the image for the screen. Choose HDR, Tone Mapping from the menu.
On this final screen, you can tweak many aspects of the photo, such as the white and black levels, the color saturation, and contrast levels. Feel free to experiment with the settings.
Click for full image.
You'll probably find that often you can just click OK to accept the defaults; the results will look impressive without much tweaking. I used a series of five photos for my HDR image, which appears on the right.
HDR isn't perfect. Because it relies on a series of photos, it's not appropriate for action photography--or, in fact, photos in which pretty much anything moves at all. It requires meticulous setup, a tripod, enough patience to configure a series of bracketed images--and, of course, the software to glue it all together at the end. But if you can deal with those shortcomings, you can make some photos that are nothing short of stunning.
Hot Pic of the Week
Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.
Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.
Click for full image.
This Week's Hot Pic: "Summer Snack," by Patrick Marcigliano, Cumming, Georgia
Patrick says: "I took this shot of my daughter at a beach house after she had just come in from the beach to eat some lunch. She was hopping up and down at the table's edge, playing hide and seek with me. I just happened to catch her when she paused for just a second to see what I would do."
http://www.ecoustics.com/pcw/howto/131612
Monday, May 28, 2007
Roundup of Universal Audio Players
A universal audio player is a machine that will play four distinct music-delivery formats: DVD-Video (which can be used for audio only), DVD-Audio, SACD, and compact disc. Each has its specific requirements -- some of which necessitate a unique set of hardware specifications -- that enable it to interface with your system. Although it has been heralded for quite a while now, and there have been sightings (much like the Loch Ness Monster up to this point), universal players are available now from several manufacturers, and in time for the Christmas buying season.
You can think of the universal audio player as, first and foremost, a DVD player. This will make its use comfortable for most consumers once they get used to a few additional connections and operational differences. The DVD-Video performance will be identical to what you’re used to with your DVD player. You’ll connect to your TV using composite, component, or S-video cables, which will allow the video portion of the signal to get to your monitor.
The universal audio player will have a digital output for the audio signal that will interface with the digital input on a receiver or A/V processor (or digital-to-analog converter for pure two-channel audio). This digital output will send a signal encoded with Dolby Digital or DTS surround sound for your external decoder to unravel. There will also be two-channel analog outputs for conventional stereo playback, if you choose to use it that way. All this is standard operating procedure for DVD, and is carried over to universal audio players. But there’s more.
The differences come in when playing back multichannel DVD-Audio and SACD. With a few exceptions (which will be explained below), these formats interface with the outside world via a set of six-channel analog outputs. These six cables (usually RCA types) carry the full 5.1 signal -- front left and right, center, left and right surround, and subwoofer (or LFE, for low-frequency effects). They must have a corresponding six-channel input, which can be found on most modern receivers, A/V processors, and purpose-built multichannel preamps. The six-channel analog outputs will carry DVD-Audio, SACD, and an internally decoded Dolby Digital or DTS signal.
Note on the Dolby Digital and DTS signal via the six-channel outputs: Most older DVD players relied exclusively on external decoders for this function, but universal audio players have internal decoding. This internal processing can be utilized via the six-channel outputs, which will take the place of the digital connection to external decoders such as a receiver. It’s your choice which to use. Since I use a multichannel preamp (without its own decoding), I use my source player’s internal decoding exclusively. If you’re using six-channel outputs, it is redundant to use the digital connection too, unless there are specific processing features in your receiver or AV processor not present in the universal audio player that you wish to use.
Choices, choices
Below is a listing of currently available universal audio players. You’ll have to check with your local dealer, but at the time of this writing, these were readily available (or will be very soon) in most markets.
Pioneer should be credited for blazing the trail for universal audio players. Though their first player, the DV-AX10 ($5000, when available), did not play back multichannel SACD (instead, SACD via this machine was two-channel only), it was compatible with all the formats listed above. More importantly, it was almost two years ahead of its time. Pioneer’s current offerings are the DV-47Ai ($1200) and DV-45A ($700). Both players offer a full suite of features, including 192kHz/24-bit audio DACs, PureCinema progressive-scan video, and full bass management. The DV-47Ai adds a proprietary digital output (for SACD and DVD-A) for use with Pioneer’s upscale receivers. It should be noted that the "i-link" will not currently interface with other manufacturers’ gear.
Onkyo has in its stable the DV-SP800 ($1000). Features include 192kHz/24-bit audio DACs and the company’s proprietary Vector Linear Shaping Circuitry (VLSC), which was included "to remove unwanted pulse noise for a smoother analog output signal." The DV-SP800 is Onkyo’s top-of-the-line DVD-Video player as well, evidenced by 108MHz/12-bit video D/A converters.
On the upper end of the price scale for the players included in this list is the Marantz DV8300 ($1600). The host of performance-enhancing features includes Cirrus Logic 192kHz/24-bit digital-to-analog conversion, Marantz's proprietary HDAM (High-Definition Amplifier Module) output stages, as well as "a separate power transformer for the audio circuit, and a zero-impedance copper grounding plate for the analog multichannel output." Marantz specifies the DV8300 with "full bass management for DVD-Video, DVD-Audio, and SACD discs."
Although scant little information is available on the Teac/Esoteric DV-50 at this time, it is undoubtedly the most ambitious of the universal audio players currently available. Built like the proverbial tank in the best Esoteric tradition, the DV-50 includes user-selectable digital filters and a chassis designed to provide shock-resistant playback of all the currently available audio formats. As can be garnered from the DV-50's $5500 price -- and evidenced by its almost 50-pound net weight -- it is a serious machine. 200212_yamaha.jpg (11611 bytes)Look for a review here in 2003.
The Yamaha DVD-S2300 ($1000) sports a host of audio/video goodies such as Faroudja’s DCDi video processing (the only universal audio player with such capability) and full bass management. The player’s hefty build quality, especially for the price, has garnered the player a ton of pre-production Internet buzz. The gold finish in the picture may or may not be available in North America; write Yamaha and tell them you want it!
200212_integra.jpg (8237 bytes)Integra has come to the party with the THX Ultra Certified DPS-8.3. Equipped with 192kHz/24-bit audio DACs and built-in Dolby Digital and DTS decoding, the Integra has some features designed purely to augment audio performance. For example, critical signals are routed through heavy-gauge cables (as opposed to circuit boards, which are prone to noise pickup according to Integra). The DPA-8.3 retails for $1200, and it's another player you'll see reviewed on SoundStage! in 2003.
There are several more players from various manufacturers that I am unclear about in terms of availability and/or actual production. The Apex Digital AD-7701 was a second-generation machine. There’s been a promised replacement, but I have not seen one. Luxman was reportedly producing two players as well, but I have not turned up any availability in North America. I expect more players to crop up at next year’s CES, and of course the SoundStage! Network will report on all of them.
Universal audio players are an exciting development for those looking to be surrounded by all the currently available multichannel-music formats. But please check with each manufacturer to ensure that a particular player’s bass-management functions will satisfy your system’s needs. If not, you can use the Outlaw Audio ICBM to compensate for any deficiencies.
http://www.soundstage.com/surrounded/surrounded200212.htm
You can think of the universal audio player as, first and foremost, a DVD player. This will make its use comfortable for most consumers once they get used to a few additional connections and operational differences. The DVD-Video performance will be identical to what you’re used to with your DVD player. You’ll connect to your TV using composite, component, or S-video cables, which will allow the video portion of the signal to get to your monitor.
The universal audio player will have a digital output for the audio signal that will interface with the digital input on a receiver or A/V processor (or digital-to-analog converter for pure two-channel audio). This digital output will send a signal encoded with Dolby Digital or DTS surround sound for your external decoder to unravel. There will also be two-channel analog outputs for conventional stereo playback, if you choose to use it that way. All this is standard operating procedure for DVD, and is carried over to universal audio players. But there’s more.
The differences come in when playing back multichannel DVD-Audio and SACD. With a few exceptions (which will be explained below), these formats interface with the outside world via a set of six-channel analog outputs. These six cables (usually RCA types) carry the full 5.1 signal -- front left and right, center, left and right surround, and subwoofer (or LFE, for low-frequency effects). They must have a corresponding six-channel input, which can be found on most modern receivers, A/V processors, and purpose-built multichannel preamps. The six-channel analog outputs will carry DVD-Audio, SACD, and an internally decoded Dolby Digital or DTS signal.
Note on the Dolby Digital and DTS signal via the six-channel outputs: Most older DVD players relied exclusively on external decoders for this function, but universal audio players have internal decoding. This internal processing can be utilized via the six-channel outputs, which will take the place of the digital connection to external decoders such as a receiver. It’s your choice which to use. Since I use a multichannel preamp (without its own decoding), I use my source player’s internal decoding exclusively. If you’re using six-channel outputs, it is redundant to use the digital connection too, unless there are specific processing features in your receiver or AV processor not present in the universal audio player that you wish to use.
Choices, choices
Below is a listing of currently available universal audio players. You’ll have to check with your local dealer, but at the time of this writing, these were readily available (or will be very soon) in most markets.
Pioneer should be credited for blazing the trail for universal audio players. Though their first player, the DV-AX10 ($5000, when available), did not play back multichannel SACD (instead, SACD via this machine was two-channel only), it was compatible with all the formats listed above. More importantly, it was almost two years ahead of its time. Pioneer’s current offerings are the DV-47Ai ($1200) and DV-45A ($700). Both players offer a full suite of features, including 192kHz/24-bit audio DACs, PureCinema progressive-scan video, and full bass management. The DV-47Ai adds a proprietary digital output (for SACD and DVD-A) for use with Pioneer’s upscale receivers. It should be noted that the "i-link" will not currently interface with other manufacturers’ gear.
Onkyo has in its stable the DV-SP800 ($1000). Features include 192kHz/24-bit audio DACs and the company’s proprietary Vector Linear Shaping Circuitry (VLSC), which was included "to remove unwanted pulse noise for a smoother analog output signal." The DV-SP800 is Onkyo’s top-of-the-line DVD-Video player as well, evidenced by 108MHz/12-bit video D/A converters.
On the upper end of the price scale for the players included in this list is the Marantz DV8300 ($1600). The host of performance-enhancing features includes Cirrus Logic 192kHz/24-bit digital-to-analog conversion, Marantz's proprietary HDAM (High-Definition Amplifier Module) output stages, as well as "a separate power transformer for the audio circuit, and a zero-impedance copper grounding plate for the analog multichannel output." Marantz specifies the DV8300 with "full bass management for DVD-Video, DVD-Audio, and SACD discs."
Although scant little information is available on the Teac/Esoteric DV-50 at this time, it is undoubtedly the most ambitious of the universal audio players currently available. Built like the proverbial tank in the best Esoteric tradition, the DV-50 includes user-selectable digital filters and a chassis designed to provide shock-resistant playback of all the currently available audio formats. As can be garnered from the DV-50's $5500 price -- and evidenced by its almost 50-pound net weight -- it is a serious machine. 200212_yamaha.jpg (11611 bytes)Look for a review here in 2003.
The Yamaha DVD-S2300 ($1000) sports a host of audio/video goodies such as Faroudja’s DCDi video processing (the only universal audio player with such capability) and full bass management. The player’s hefty build quality, especially for the price, has garnered the player a ton of pre-production Internet buzz. The gold finish in the picture may or may not be available in North America; write Yamaha and tell them you want it!
200212_integra.jpg (8237 bytes)Integra has come to the party with the THX Ultra Certified DPS-8.3. Equipped with 192kHz/24-bit audio DACs and built-in Dolby Digital and DTS decoding, the Integra has some features designed purely to augment audio performance. For example, critical signals are routed through heavy-gauge cables (as opposed to circuit boards, which are prone to noise pickup according to Integra). The DPA-8.3 retails for $1200, and it's another player you'll see reviewed on SoundStage! in 2003.
There are several more players from various manufacturers that I am unclear about in terms of availability and/or actual production. The Apex Digital AD-7701 was a second-generation machine. There’s been a promised replacement, but I have not seen one. Luxman was reportedly producing two players as well, but I have not turned up any availability in North America. I expect more players to crop up at next year’s CES, and of course the SoundStage! Network will report on all of them.
Universal audio players are an exciting development for those looking to be surrounded by all the currently available multichannel-music formats. But please check with each manufacturer to ensure that a particular player’s bass-management functions will satisfy your system’s needs. If not, you can use the Outlaw Audio ICBM to compensate for any deficiencies.
http://www.soundstage.com/surrounded/surrounded200212.htm
Put the Compact Disc Out of Its Misery
This spring, the compact disc celebrates the 20th anniversary of its arrival in stores, which puts the once-revolutionary music format two decades behind Moore's Law. The IBM PC, introduced about a year and a half earlier, has been revved up a thousandfold in performance since 1983. But the CD has whiled away the time, coasting on its Reagan-era breakthroughs in digital recording and storage. The two technologies, the PC and the CD, merged not long after their debuts—try to buy a computer without a disc player. But the relationship has become a dysfunctional one. The computer long ago outgrew its stagnant partner.
To the new generation of music artists and engineers, "CD-quality sound" is an ironic joke. In recording studios, today's musicians produce their works digitally at resolutions far beyond the grainy old CD standard. To make the sounds listenable on antiquarian CD players, the final mix is retrofitted to compact disc specs by stripping it of billions of bits' worth of musical detail and dynamics. It's like filming a movie in IMAX and then broadcasting it only to black-and-white TV sets.
It doesn't have to be this way. The modern recording studio is built around computers, Macs or PCs. Beefed up with high-performance analog-to-digital converters and super-sized disk drives, they digitize music up to 192,000 times per second, storing it as 24-bit data samples. That "192/24" standard captures more than a thousand times as much detail as the CD's "44.1/16" resolution. Moreover, this music data is just another computer file, an icon on a desktop. Double-click it, and it plays. It would play on your home computer, too, if you could get your hands on it. All you would need to enjoy studio-quality sound at home are high-end speakers or an amplifier with digital connections to your computer. That's the "digital hub" scenario touted by Bill Gates, Steve Jobs, and others. Plug everything into a home network, load up the computer with tunes, and press play from anywhere in the house. A three-minute pop song in 192/24 format fills about 200 megabytes of hard-disk space, which means Dell's latest 200-gigabyte drive could hold nearly a thousand of them.
But instead of gearing up for digital home hubs, record companies have rolled out two more shiny-disc formats: DVD-Audio and Super Audio CD. Both sound great, but you're forgiven if you haven't heard of them. Following the radical makeover of consumer electronics in the past two decades, these discs have wandered in like Rip Van Winkle, unaware how behind the times they are.
In sound quality, at least, each disc brings the listening experience up to modern standards. DVD-A, developed by an audio industry working group, pumps up the old CD format 500 to 1,000 times in data density to match that now used in studios. SACD, on the other hand, is based on a new form of digital recording developed by Sony and Philips that converts sound waves into bits (and back again) more smoothly. Both bring studio data to the listener, bit for bit, and include extra surround-sound channels for home-theater systems. Properly engineered, their improvement over CD sound is striking. Can the average person hear the difference? Instantly. As Fred Kaplan noted this past summer in Slate, it's enough to make you buy new speakers.
Yet both kinds of discs, despite being developed in the 'Net-head late '90s, are odd throwbacks to the pre-PC era. Most obviously, they're the same size as the original CD. Can you name any other digital device that hasn't shrunk in 20 years? The players for them are bulky, closer in size to Sony's first CD decks than to Apple's iPod, which holds 400 albums rather than just one.
Flip one of the players over, and you'll find another retro sight: analog output jacks. To prevent buyers from running off bit-for-bit copies of the new discs, gear-makers have agreed not to put digital ports on either DVD-A or SACD players. Yet old-fashioned analog connections erode pristine digital sound and are prone to interference from televisions, lights, and computers—the objects they'll be placed next to in modern homes.
The real deal-breaker is that a stand-alone player is the only kind available. By manufacturers' consensus, there won't be any network ports on the players, nor will there be any DVD-A or SACD drives available for computers. Some makers are promising a digital link from the player to a home-theater console, but it'll be deliberately incompatible with any of the jacks on a computer. In bringing the CD up to date with the PC, the music industry is also trying to split the two technologies asunder again.
It's no wonder that gearheads who buy the latest, greatest everything have ignored DVD-A and SACD in favor of MP3 players and CD burners. Computer-friendly music formats let you archive hundreds of albums on a laptop, create custom playlists that draw from your entire collection, and download them to portable players smaller than a single CD jewel box. Today's fans want their music in a form that fits the pocket-sized, personalized, interconnected world of their computers, cameras, phones, and PDAs. Asking digital consumers to give that power back in exchange for a better-sounding disc is like offering them a phonograph needle.
Paul Boutin is Wired's managing editor for blogs.
http://slate.msn.com/toolbar.aspx?action=print&id=2076336
To the new generation of music artists and engineers, "CD-quality sound" is an ironic joke. In recording studios, today's musicians produce their works digitally at resolutions far beyond the grainy old CD standard. To make the sounds listenable on antiquarian CD players, the final mix is retrofitted to compact disc specs by stripping it of billions of bits' worth of musical detail and dynamics. It's like filming a movie in IMAX and then broadcasting it only to black-and-white TV sets.
It doesn't have to be this way. The modern recording studio is built around computers, Macs or PCs. Beefed up with high-performance analog-to-digital converters and super-sized disk drives, they digitize music up to 192,000 times per second, storing it as 24-bit data samples. That "192/24" standard captures more than a thousand times as much detail as the CD's "44.1/16" resolution. Moreover, this music data is just another computer file, an icon on a desktop. Double-click it, and it plays. It would play on your home computer, too, if you could get your hands on it. All you would need to enjoy studio-quality sound at home are high-end speakers or an amplifier with digital connections to your computer. That's the "digital hub" scenario touted by Bill Gates, Steve Jobs, and others. Plug everything into a home network, load up the computer with tunes, and press play from anywhere in the house. A three-minute pop song in 192/24 format fills about 200 megabytes of hard-disk space, which means Dell's latest 200-gigabyte drive could hold nearly a thousand of them.
But instead of gearing up for digital home hubs, record companies have rolled out two more shiny-disc formats: DVD-Audio and Super Audio CD. Both sound great, but you're forgiven if you haven't heard of them. Following the radical makeover of consumer electronics in the past two decades, these discs have wandered in like Rip Van Winkle, unaware how behind the times they are.
In sound quality, at least, each disc brings the listening experience up to modern standards. DVD-A, developed by an audio industry working group, pumps up the old CD format 500 to 1,000 times in data density to match that now used in studios. SACD, on the other hand, is based on a new form of digital recording developed by Sony and Philips that converts sound waves into bits (and back again) more smoothly. Both bring studio data to the listener, bit for bit, and include extra surround-sound channels for home-theater systems. Properly engineered, their improvement over CD sound is striking. Can the average person hear the difference? Instantly. As Fred Kaplan noted this past summer in Slate, it's enough to make you buy new speakers.
Yet both kinds of discs, despite being developed in the 'Net-head late '90s, are odd throwbacks to the pre-PC era. Most obviously, they're the same size as the original CD. Can you name any other digital device that hasn't shrunk in 20 years? The players for them are bulky, closer in size to Sony's first CD decks than to Apple's iPod, which holds 400 albums rather than just one.
Flip one of the players over, and you'll find another retro sight: analog output jacks. To prevent buyers from running off bit-for-bit copies of the new discs, gear-makers have agreed not to put digital ports on either DVD-A or SACD players. Yet old-fashioned analog connections erode pristine digital sound and are prone to interference from televisions, lights, and computers—the objects they'll be placed next to in modern homes.
The real deal-breaker is that a stand-alone player is the only kind available. By manufacturers' consensus, there won't be any network ports on the players, nor will there be any DVD-A or SACD drives available for computers. Some makers are promising a digital link from the player to a home-theater console, but it'll be deliberately incompatible with any of the jacks on a computer. In bringing the CD up to date with the PC, the music industry is also trying to split the two technologies asunder again.
It's no wonder that gearheads who buy the latest, greatest everything have ignored DVD-A and SACD in favor of MP3 players and CD burners. Computer-friendly music formats let you archive hundreds of albums on a laptop, create custom playlists that draw from your entire collection, and download them to portable players smaller than a single CD jewel box. Today's fans want their music in a form that fits the pocket-sized, personalized, interconnected world of their computers, cameras, phones, and PDAs. Asking digital consumers to give that power back in exchange for a better-sounding disc is like offering them a phonograph needle.
Paul Boutin is Wired's managing editor for blogs.
http://slate.msn.com/toolbar.aspx?action=print&id=2076336
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