Controversy over UltraBit review in August issue
Robert Harley -- Wed, 07/30/2008 - 14:50
My review of the UltraBit Platinum CD treatment in the August issue of The Absolute Sound understandably generated some controversy. I say “understandably†because it’s hard to imagine a mechanism by which a fluid applied to a CD’s surface could affect sound quality, never mind introduce an analog-like variability in such aspects of the sound as timbre and soundstaging.
I don’t know how UltraBit Platinum (or any other CD treatment) works, but I have first-hand experience that suggests that a CD’s optical properties can affect the sound in an analog-like manner even though the datastream remains unchanged.
In the late 1980s, I worked in a CD mastering lab. In addition to being part of a six-man team that designed and built CD (and Laserdisc) mastering machines, my job included correlating problems in replicated discs with anomalies on master tapes and the mastering process. (I co-wrote, with Ray Keating, an Audio Engineering Society paper on this subject called “CD-V Signal Optimization.â€)
A CD-replication client claimed that the discs we made sounded inferior to his master tape. I performed a bit-for-bit comparison between the master tape (3/4†U-Matic tape in the PCM-1630 format) and the replicated disc using a CD-ROM pre-mastering computer. Not surprisingly, the data were bit-for-bit identical. I was unable to verify the client’s claim that the disc sounded different from the master because I couldn’t listen to both sources through the same D/A converter.
My colleagues—all “bits is bits†engineers—dismissed the client’s claim as mere delusion in light of the bit-for-bit accuracy of the disc to the master tape. In their view, we had done our job in delivering a CD with a bitstream that was identical to the master.
Nonetheless, I wanted to pursue this question, and cut another master from the same tape, but on a different mastering machine. The client reported that the discs made from this second master sounded significantly better than the first discs. With two CDs, I could now compare them for myself decoded through the same D/A converter. The client was correct; the second CD sounded smoother, more spacious, and less “digital.†He didn’t describe the differences in those terms; to him, the first disc was simply missing his musical expression.
There were no manufacturing differences between the discs; neither had uncorrectable errors or other problems that are routinely checked during QC. My curiosity was piqued, so I had the jitter on both discs analyzed using a specialized piece of test equipment. To understand the concept of jitter in a CD, some background on how the CD works is necessary.
Digital data are stored on the CD in “pits†(indentations in the disc) and “land†(the flat disc surface). The transition from pit-to-land or land-to-pit represents binary “one.†All other surfaces (pit bottom or land) represent binary “zero.†The pit and land structures don’t represent the data directly. Rather, an encoding scheme called “eight-to-fourteen modulation†(EFM) creates patterns of data in which successive binary “ones†are separated from each other by a minimum of two “zeros†and a maximum of ten “zeros.†This produces nine discrete pit and land lengths on the disc.
The playback laser beam is reflected from the disc to a photodetector that converts light to an electrical signal. The nine discrete pit and land lengths produce a amplitude-modulated signal at the photodetector composed of nine discrete sinewaves, which vary in frequency from 196kHz (corresponding to the longest pit or land length) to 720kHz (corresponding to the shortest pit and land lengths). The digital data are contained in the sinewaves’ zero-crossing transitions.
The jitter analyzer counts the exact frequency of each of the nine sinewaves, and then graphically plots their frequency distribution. The distribution is Gaussian, with most of the pit and land lengths falling very close to the ideal. On the first disc, the distribution was extremely wide, with large variations in the pit and land lengths. On the second disc, the distribution was sharply defined and the curve was very narrow. In other words, the first disc had a greater amount of jitter encoded in the physical structures that represent the digital data. You could see this by looking at the signal from the photodetector; the so-called “eye pattern†was a little ragged on the first disc compared to that of the second disc. (There’s a reason the second disc had lower jitter; the mastering machine on which it was cut had a more sophisticated rotational-servo control than that of the first mastering machine.)
Note that the pit- and land-length variations were not great enough to be interpreted incorrectly; a binary “one†was never mistaken for binary “zero.†The datastreams were identical after decoding. Similarly, the eye pattern from a CD-R is significantly cleaner looking than that of a replicated CD, although the data remain unchanged. Virtually everyone who has compared a CD-R to the CD from which it was burned reports that the CD-R sounds better than the original.
It’s clear to me that the quality of the signal at the photodetector affects the disc’s sound. I don’t know how variations in the eye pattern find their way into the analog output signal; the photodetector’s output undergoes a huge amount of decoding, error correction, de-interleaving, and other processes to extract the raw PCM audio data that are converted to analog by the DAC. Nonetheless, there’s no question in my mind that a disc’s optical properties, which directly influence the eye pattern, introduce an analog-like variability in sound.
It is not such a great leap of faith to suggest that a fluid applied to the disc could introduce the kinds of sonic differences I heard in the listening room after applying UltraBit Platinum. It’s a mistake to dismiss what your ears tell you because the phenomenon in question cannot yet be explained.
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robert_harley6 wrote:The jitter analyzer counts the exact frequency of each of the nine sinewaves, and then graphically plots their frequency distribution. The distribution is Gaussian, with most of the pit and land lengths falling very close to the ideal. On the first disc, the distribution was extremely wide, with large variations in the pit and land lengths. On the second disc, the distribution was sharply defined and the curve was very narrow. In other words, the first disc had a greater amount of jitter encoded in the physical structures that represent the digital data. You could see this by looking at the signal from the photodetector; the so-called “eye pattern†was a little ragged on the first disc compared to that of the second disc. (There’s a reason the second disc had lower jitter; the mastering machine on which it was cut had a more sophisticated rotational-servo control than that of the first mastering machine.)
Note that the pit- and land-length variations were not great enough to be interpreted incorrectly; a binary “one†was never mistaken for binary “zero.†The datastreams were identical after decoding. Similarly, the eye pattern from a CD-R is significantly cleaner looking than that of a replicated CD, although the data remain unchanged. Virtually everyone who has compared a CD-R to the CD from which it was burned reports that the CD-R sounds better than the original.
It’s clear to me that the quality of the signal at the photodetector affects the disc’s sound. I don’t know how variations in the eye pattern find their way into the analog output signal; the photodetector’s output undergoes a huge amount of decoding, error correction, de-interleaving, and other processes to extract the raw PCM audio data that are converted to analog by the DAC. Nonetheless, there’s no question in my mind that a disc’s optical properties, which directly influence the eye pattern, introduce an analog-like variability in sound.
I'm curious - have your or your colleagues attempted to discover how the physical differences on the discs manifest themselves into audible differences? The only real study I've seen relating to this is the Prism paper from over 10 years ago, which doesn't offer any good conclusions.
I would certainly be interested in any insight you may have. The prevailing audiophile mentality seems to be of finding the "best" source (i.e., a particular CD pressing), rather than investigating why physical differences on the disc affect the sound at all. One would think equipment manufacturers would jump at the chance to figure out what is going wrong and design their equipment to eliminate the problem.
Good question. I think that Philips has some insight into this question, but that they choose not to discuss it in public. It raises issues that they would rather not have raised. In a discussion with a Philips engineer once, I brought up the issue of pit jitter affecting the analog output signal. He gave a knowing smile and then disavowed any knowledge of the phenomenon. Philips, incidentally, was responsible for the optical aspects of CD, and Sony contributed the decoding chips, broadly speaking.
robert_harley6 wrote:Good question. I think that Philips has some insight into this question, but that they choose not to discuss it in public. It raises issues that they would rather not have raised. In a discussion with a Philips engineer once, I brought up the issue of pit jitter affecting the analog output signal. He gave a knowing smile and then disavowed any knowledge of the phenomenon. Philips, incidentally, was responsible for the optical aspects of CD, and Sony contributed the decoding chips, broadly speaking.
Interesting. How recently was that discussion?
I know at least a handful of people have indicated that they can rip digitally identical CDs (that sound different) back to their workstations, and when played back off of the hard drive, they sound identical, which seems to make sense. Is that something you have tried?
Obviously there is a large installed base of players, and producing discs that sound best on those is a good idea, but I'm mystified that there hasn't been more research into developing players where this is no longer an issue. Some folks even seem offended by the suggestion that a "bad" CD could sound just as good as a "good" one with the right equipment.
It's not surprising that two discs that sound slightly different but deliver identical datastreams sound the same when ripped to a hard-disk.
To answer your question about my encounter with the Philips engineer, that ocurred around 1997.
Thanks Robert.
Maybe I'm in the minority, but I'd certainly be interested in *why* these things are an issue.
CD cleaners have been on the market for years, along with rings, CD Stoplight, and other solvents. HP's recommended several over the years. Did THAT generate any controversy???
Why should this "controversy" be happening now, 15 years after CD Stoplight??? I"m aghast that people question it.
By the way, I bought the UltraBit Platinum for no other reason that to see if it made a DISCERNIBLE difference. I do hear the difference, but I also think there is a trap in Mr. Harley's pronouncement, in particular : his access to equipment [that is] superior to most people's will cause a "rave" of something that for people with, say, NAD equipment, (heck, even my Hurricanes/Usher 718s, with Transparent MM2, Shunyata Python Helix power cords [although I bet it's using that Arcam FMJ-22 as the preamp section [temporarily]) will not be as apparently astounding as it was with say, Wilson Alexandrias, or Magicos or those 30k speakers JV and WG use. And therein lies the rub.
What would be logical is to try it on a system in the 3k region or 5k so you can determine how much of what you hear on a 150k 100k, 40k, or even (like that's cheap!!!!!) 20k system is due to the resolution of your system. It should be quite obvious that a state-of-the-art system is, by definition, capable of demonstrating the effects more immediately than a more modest system. (And using the SimAudio Andromeda is NOT, by the way, everyday equipment! :D ) Keep that in mind. Of course, you're not likely to have a Creek Destiny or a NAD, although you did have a Naim, but nonetheless, in a more global sense, when reviewers make pronouncements, they anger people so frequently because it takes a superior system to demonstrate certain effects. And many people have not "tuned" their rooms for 1st, 2nd, and 23,666 reflections. They should, but even in 2008, how many have actually done this??? (And tube traps are a great answer, but require many, many, many hours of pushing them down the wall and turning the seam to get maximum effect. As I've said before, a turn as little as 1/100" can make your jaw drop. Just ask my friend, the former concert pianist.) These days, people complain about the slightest thing that their equipment doesn't demonstrate, and, the Web being what it is, generates 50 responses before you've even responded once. It's a losing battle, unless you are on a par with the average system of your readers, which most of the TAS reviewers are not (and why should they be?!?!?! The "pronouncement" will have more credibility with Magicos than they will with say, Spica TC-50s, a perfectly good speaker, but not revealing in the same way that Magicos are). With the average system, cobbled together to make it "sound good" instead of how a nylon guitar expands into space in real life (which again, how many of your readers have ever even heard? Not many, I'll bet), the complaints are based on lack of experience -- also known as ignorance. Ignorance in the sense of: haven't heard it, so don't truly know if the reviewer's right or not, and don't have equipment equivalent to theirs.
The stuff's okay on my Hurricane/Usher/Transparent/Nordost/MIT CVT 350/Arcam stuff, but not the "astounding" effect Mr. Harley heard. I didn't, however, buy it expecting the effects to be the same: I bought it because I wanted to see how much it improved MY system. I could take it or leave it, personally, because it's not that much different than the L'Art du Son or Optrix cleaners HP recommended 2 years ago -- at least not in the midbass, upper bass and lower midrange, which is where I, personally, care to hear an improvement. Still, it's no more or less valid a choice for cleaning CDs than they are.
So, I repeat, WHY is there a controversy? This is flat out stupid, unless the arguers have, in the past, objected to any -- and ALL -- CD treatments.
I think they're objecting to Mr. Harley more than the component, and I think that ever since he wrote the Cambridge Audio 840 review. By the way, as I have posted in the "Cambridge vs Rega Apollo" thread, I like the Cambridge, but not to the degree Mr. Harley did. Therefore, his pronouncement, since it's a subjective one, annoyed the hell out of half of AA. Of course, they hadn't heard it, but that's beside the point. And if they did, they objected that he declared it the best CD player under $5k (which, in retrospect, wasn't the best headline for copy I've seen. Not because it may not be "all that" but just because it made people say, "well, has he heard EVERYTHING under 5k?" which of course, he couldn't possibly do. So, that sank THAT boat, and I suspect the UltraBit's creator is either going to benefit, or be scorned simply because it was Mr. Harley who wrote the review. If say, Neil Gader wrote it, I would bet my life that the review would not have generated such a tsunami: more like a surfer catching a good wave.
This article is simply delivering false information. I'm an engineer working in acoustics, and typically reading optical media (CD, DVD) requires that the digital data be read and buffered (several seconds of data potentially) before it is delivered to a system's digital to analog converter. The jitter you are referring to occurs in the reading of the binary data stored on the disc, which is in the process of converting 'pits' to ones and zeros (binary). Moreover, the CD data is encoded for error correction algorithms to help in the decoding of scratched CD's and pit alignment deviations (the cause of you refer to as jitter above). The beauty of the digital media is that once you have extracted error free binary data, it is exactly the same from CD to CD. There is no question about this - it is EXACTLY the same. Any sonic difference would only occur in the delivery of the digital data to the speaker (digital to analog conversion). Any other sonic difference can only be attributed to the subjective ear. The optical jitter refered to above has nothing to do with the quality of the musical data represented by the one's and zeros of the music itself.
Have you come to this conclusion on the basis of your own listening, or simply because two CDs with identical data "should" sound the same?
I've experienced similar results as Rudy, but I don't think it's a debunking of UltraBit, but rather an alternate solution to the problem. I've never used UltraBit and I have no vested interest in promoting their products. I'm not an engineer, but I try to think like one from time to time. It seems that "bits is bits" argument ignores the time domain of how many bits should occur during a given time interval. What is implied by all of the above information on this thread is that there are less than ideally burned physical pits on some CDs and there are other CDs that are perfectly "burned". If this is being recovered from a real time device such as a CD player, then the velocity of the spinning CD, the quality of the burned pits, and the time-domain information must all be re-combined to properly recreate the elements of the recording. If the electronics are getting overworked in trying to get the bits into the proper time-domain because it's reading a bunch of poorly burned bits, then I suppose this could cause some less than perfect recreations. The music must go on, so if the buffer isn't full or is poorly constructed just before it hits the final digital output stream, so be it. Perhaps the UltraBit gives greater contrast for the laser to read which results in a higher quality digital stream? I don't know, but I could see a case for argument.
What I do know is that I've created a computer based music server where I rip all of my CDs to AIFF lossless with maximum error correction turned on during the ripping. In theory, I can take a less than ideal quality CD and read and re-read it until I've recreated all of the bits and time-domain information. On playback, I use many different software suites, but I always use the ASIO drivers (bit perfect playback), and I use the maximum memory buffer to feed my DAC. I have a well known and regarded SACD player. If I play a CD through the SACD player standalone, or feeding the DAC from the SACD player, both presentations sound quite nice. However, if I feed the same ripped CD data via the ASIO drivers at 24/96 to the DAC, the sound is an order of magnitude better than listening to the CD in real time from the CD/SACD player. Perhaps because it's feeding the bits and time-domain info to the DAC in a clean, well buffered manner with no error correction occuring? I don't know, but I do know that I always use my music server to "listen to my CDs" now because the same CD sounds worlds better coming out of the computer. It's more dynamic, more sharply defined, and has this unique solidity that I hadn't heard on my digital front end before.
Yes, "bits is bits" but some methods are better at getting those bits to our ears through real-time acrobatics vs starting with a cleaner bucket of bits in the first place. I bet UltraBit works better on CD players that don't have a strong error correcting/buffering mechanism.
Is it possible that putting fluid on a disc 'fills in" some of the pits and therefore has the potential to change the pit to land and land to pit transitions and therefore IS changing a 1 to a 0 or a 0 to a 1? If that were the case, you wouldn't think a disc would sound better, you would think it would generate random noise, but who knows?
Think of a photograph. Especially with portraits, we frequently de-sharpen (in digital photography, we're actually eliminating resolution) in order to make the picture look "better".
Could that be what's happening here?
I still don't see how two discs, each with the same lands and pits, therefore representing the same digital words, can sound different.
I myself cannot understand how if the datastream is identical it can sound different. It seems to me, scientifically, that the "coating" or "application" may not be affecting the datastream at all but perhaps the internals of the machine. Imagine what that could mean for the electronics or circuits.
However, I spent many years in university and used microscopes DAILY. First rule: ALWAYS clean the lenses before use. Clean lenses give better resolved images. Perhaps whether it is affecting the lens is another possibility.
But how it affects the sound is frankly irrelevant. Whether it makes it better is the question, and if it does then it is to be commended. But the catch is "whether it does". This is subjective, and only the prospective buyer can decide that. Comparing a direct A/B test between two amps of dissimilar cost (which I have done in my own system) showed that differences and one being BETTER is a real fact. But many are going to think this is grasping at straws, at best. Personally, if it works, so be it. I myself am not going to rush out as my sound is very good. Spending a bit on sound traps, perhaps a better cable or positioning the speakers (free and the most effective way) is probably the most people will go to extract that last bit of detail, but some will go further.
I think perhaps it is the fact the resolution of CD (digital, if you will) could be TOO sharp and some think softening the edges perhaps is best. This is easily proved in that if the sharpness feature on a TV is too high the edges become grainy, too resolved. But if the sharpness is toned down a bit, the image becomes more "soft", pleasing to the eye.
I appreciate the review but frankly with added resources I would rather save up for a new DAC or a couple of better cables rather than something a lukewarm cloth can do just as well
The "bits is bits" theory (that identical datastreams sound identical) can easily be tested as MarkT describes; rip a CD to a music server and compare the sound from the hard drive to the sound from a CD transport feeding the same DAC. You can also perform a bit-for-bit comparison between the two; you'll find that virtually all the time the bits are identical. Yet the sound is different.
I was in Meridian Audio's room at a CES show many years ago when CD-R was first available. Recording engineer Peter McGrath was sitting next to me. Meridian's Bob Stuart played a CD that Peter had engineered, and then without saying anything, put a CD-R in the player and pressed "Play." Seconds after the music started, Peter jumped out of his seat and exclaimed "That's impossible!" The improved sound from the CD-R was obvious. How can a copy sound better than the original? CD-R has better-shaped pits than a replicated CD, and produces a cleaner "eye pattern" from the photodetector.
UltraBit Platinum can't fill in the pits of a CD because they are sealed under the polycarbonate of the disc's playing side. If you'd like to learn more about the structure of CDs and CD-Rs you may click on the link How it works Technical White Paper at http://www.UltraBitPlatinum.com that's the fourth link down at the left side of the homepage. It's been my experience that every standalone CD and DVD duplicator inverts the polarity of the music of the copied disc, at least if it's in a PCM 44.1 kHz 16 bit format relative to the copied disc. It's also my experience that computers don't invert the copy unless the operator chooses the inversion option.
I myself have not done this test, but if it is true, are you then suggesting that everyone with CD collections, such as I, rip EVERY recording to CD-R and use them as the reference? I am not debating with on whether the copy could be better or not, but the logistics of what you are suggesting should imply that it would be wise to take stock in CD-R.
Dear Everybody,
As a former Audiopsycotic ( cured since losing $$$ by investing in Melos, inc.!), who knows Nada about technology, but now has a modest system to remind me what the Real AS is, I end up buying all variety of tweeks based on "expert" advice.
So, in the area of CD Treatments, I tried CD Clarifyer-It stridently Sucks in My System; Optrix, which is a bit of a "clarifyer" with a tradeoff of some increased brightness; an Old alcohol-based fluid, which is actually rather Better IMS.
Using Bedini's First gadget, however, actually does a lot more in te right direction thany Any of the above,.. again, IMS.