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In Reply to: RE: Because some transports sound better than others posted by Sordidman on October 20, 2014 at 11:45:21
I am asserting that transports "sound" only through the DAC and, to the extent that the DAC input, clock and power circuits are fully up to snuff, the transport will have no sound barring problems with downstream amplifiers. (This is the ideal, and to the extent that this ideal is not attained, one does not have a true reference system.)
With a well set up system, there are existing DACs where the remaining transport differences are small, making it a matter of opinion whether differences are worth worrying about. If they matter, then there is a good chance of improving the sound by adding isolation devices between the transport and the rest of the audio system. These include various devices in the signal path such as reclockers, USB to I2S or SPDIF converters, USB hubs, some with optical isolation or other forms of galvanic isolation. These also include isolation devices in the power wiring and providing noise isolation between digital devices and analog devices. Similarly, careful attention may be needed to signal and power cabling. Even something like moving components or changing the cable dress may affect sound, and if so this is a strong indication of an unstable system.
I am also saying that if one experiences an "unstable" system it is not an indication of a superior system that is somehow more "resolving". It is an indication that something is wrong that warrants fixing. Steps taken to reduce susceptibility to interference in DACs and amplifiers are of benefit even if the digital transport emitted zero noise, because there are other electrical devices that generate interference.
I am also saying that the subjective and objective testing and reviewing of audio equipment should include operating in noisy environments that show the equipment in the worst possible light, thereby driving manufacturers to produce products that deliver their full performance in all realistic electrical environments.
I am not saying that "bits are just bits". I am saying that bits should be just bits and that this ideal can be approached ever closer if the market demands this.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Follow Ups:
Transports sound different regardless of anything any DAC may or not be doing "wrong."
"" adding isolation devices between the transport and the rest of the audio system"
In the case of the VRDS-NEO, - more information just makes it to the DAC. There are reasons and explanations as to why, and these are born out in listening: and are independent of any isolation devices. We know this through extensive testing.
Sprezza asserts that his Sim Audio Mind sounds different than his Bryston BP-2. He uses the same DAC, the same cable to the DAC. The transports sound different, the DAC is in no way at fault.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
"In the case of the VRDS-NEO, - more information just makes it to the DAC"
This is complete and utter BS. There is no "information" on a CD other than the 1's and 0's that were placed there during the mastering and production process. If you are lucky, the best you can hope for is to get these back correctly and then turn them back into sound without any further degradation. The problem with inferior transports isn't the lack of information, it is the extra noise that makes it through an inferior playback chain and masks such information as was on the original disk. (Which, by the way, in case of Redbook, is already significantly less than what would be on a good quality analog master tape.)
In some cases (more than you might like to admit) all of the "information" that got stamped or burned on to the disk that expensive nonsensical NRDS-NEO "read" have already passed through a lowly Plexor drive. Not the situation at all with an LP on a Goldman turntable or a reel to reel tape on a Studer deck unless it was a bogus digitally mastered "analog" recording.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
S
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
No read errors on a decent $40 computer optical drive with an undamaged disk. Zero. Verified by accurate rip for commercial CDs and verified against master WAV files for CDs that I have mastered. Zero errors, unless the disk has obvious damage such as scratches or is a CDR that has been stored at hot temperatures such as in a car. Over 97% of all disks that I have ripped were free of errors and most of those with errors had no audible damage, even when listening specifically at the point where the error occurred. There were a few that had lots of clicks, but they looked like they had been used for a game of Frisbee with a dog.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Born out by listening tests, & widely accepted & undisputed superiority.
In short, no one who has compared it, remains unconvinced.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Listening tests are a tedious and unreliable way of detecting data errors, compared to a direct comparison of the delivered bits vs. the correct bits. People may prefer expensive transports and they may be actually hearing superior sound, but if so the reason is not likely to be associated with the lack of data errors reading the CD, unless the drive in the comparison player was broken.
As to live playback, this depends on the way that the device works to do the CDA error correction. This comes in two levels of correction, plus a level of interpolation plus a level of muting. Most disks have no errors that require the second level of correction. For master disks that I burn there are strict limits on the number of C1 errors corrected and the limit is zero on the number of C2 errors corrected, otherwise I junk the "coaster". This provides the needed tolerance for wear and tear.
I feel sorry for people who have these expensive transports when they suffer wear and tear or laser problems and no longer work reliably, skip, etc... The same thing happens with the cheap computer drives like the Plexor that I use, but it's a 10 minute drive swap (no tools required) and the replacement part is under $50. My drive comes with software that diagnoses disks and plots the number and location of the various types of errors.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
The laser's reading ability: as we've seen improves whenever a more consistent and accurate speed is achieved by the motor spinning the disc, and when the disc doesn't wobble: (clamping mechanism).
""As to live playback, this depends on the way that the device works to do the CDA error correction.""
Yes and no. CDA data correction, is not all it's cracked up to be, - due to "A." (less wobble by clamping mechanism).
""For master disks that I burn"
Not relevant or applicable to a playback situation.
Of course, as we've seen with much of this stuff, - theoretical "shoulds" are proven wrong quite often.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
My comments about the lack of bit errors on CD playback are based on years of experience with hundreds of disks, a small fraction of which gave problems. This caused me to seek out and obtain the necessary tools to understand what was going on. This is not a theoretical issue, or a question of "should".
CD players are not getting bit errors on playback on undamaged disks unless the players are broken. A cheap transport may sound worse than an expensive one, but it is extremely unlikely that the cause is bit errors. If you want to verify this for yourself, just take the two CD transports under test and feed their SPDIF output into an SPDIF input of a computer sound card and capture WAV files of the two outputs. You can then use an audio editor to difference the two files and count the errors, if any. Once you've identified their location(s) you can then play clips and see what the errors sound like.
Unless you have actually studied the presence or absence of bit errors as I have, you have no basis for positing a technical cause for sonic defects that you may have heard.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Tony, I have not gotten too involved in the transport debate, but if to condense your view in the briefest of ways, distinct differences in the sound of transports, that being defined as an optical disc transport, or file player, computer, streamer etc, should be attributed to flaws in the DAC design, is that correct?
Not quite. The DAC is the primary place of attack to improve sound in digital audio playback.
The playback chain consisting of digital transport, DAC, and analog amplifiers is a system and its performance has to be evaluated as such. The chain reads the media and generates a string of bits that get clocked, converted to timed samples, converted to a continuous analog stream and then amplified. Reading the media and generating a stream of bits is a solved problem, but the process of doing so generates unwanted noise byproducts. These pollute the operation of downstream components and degrade the sound. There are three ways to fix this: have the transport produce less noise, isolate the transport from the sensitive components, and make the sensitive components less sensitive.
It seems pretty clear that the DAC, as the place where the noisy digital electronics meet the sensitive analog electronics,is the primary place where the noise battle needs to be fought. The second place where unwanted coupling comes in is through power wiring, and the third place is through cabling. It is possible to reduce the noise generated in the computer by "gold plating" the computer, but the economics seems to favor "gold plating" the DAC and amplifiers, especially since there will still be noise from other computing devices even if the transport has been made noiseless by putting it into a Faraday cage with Tempest grade red-black separation as used with military encryption devices.
That we are still arguing over physical machines and whether they can correctly read bits off of media, shows how hopeless the "high end" market is. I have avoided this marketplace for a long time and concentrated instead on equipment made to be sold to professional audio engineers, who are by and large more technically competent that audiophiles.
I hope it remains warm enough to enjoy your Italian car. It's too cold and damp now in Vermont for fun cars as we await the start of ski season.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Hi Tony:Very little to disagree with your well worded post. I don't agree about Pro Audio gear, I have gone that route with great dissatisfaction, but that is just me.
So in regards to your reply, how would you account for some audiophiles who have superbly set up, high quality gear, yet hear big differences in computer O/S, add ons like Jplay, playback software, and even updates to playback software, and best of all, USB cables?
A perfect example is Mercman. He has superb gear, and clearly knows how to set it up..Ayre, Wilson, MSB, and a number of very good cables, sources, power products etc, yet he consistently says he hears differences in O/S updates, USB cables, playback software etc.
P.S. Nice and balmy where I am...my baby is gripping the roads nicely.
Edits: 10/23/14 10/23/14
Hearing differences is not the end of the world. I hear differences if I move my head half an inch. Every seat in a concert hall sounds slightly different. So it's a concern only if one hears significant differences. If one does hear significant differences and if they are consistent then it is probably possible (with a huge amount of effort) to come to the bottom of the situation and figure out how these differences are happening. As far as I know there is no DAC that is perfect when it comes to isolation. As Thorsten explained, the DAC can be perfect but the amplifiers sensitive to interference. (My Focal powered monitors pick up my cell phone if it's within a few feet.)
There are also people who hear differences that aren't present in the audio equipment or environment but that merely exist inside their own head. I don't believe this covers Merman, since he seems to be a straight up guy. And besides, he has Lucy to keep him honest. Perhaps you should ask Lucy your question? :-)
Also, keep in mind that a Maserati is a more finicky car than a Mercedes, so expensive and high performance is not necessarily the same as stable and reliable. I had a Citation II tube amplifier back in the 60's and 70's and it sounded great when it wasn't blowing up KT88s, etc... I then inherited a Mac 275 that was solid and reliable, but I could never stand its sound. (I was annoyed that I inherited the Mac, because I had advised my grandfather to get a pair of Marantz 9s and he ended up with the Mac 275. However, it might have been a space problem with his custom installation.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
We are talking differences that do not include changes in listening position or physical space. Same chair, same chain, but switching out ONE item like a USB cable or an O/S update.I think environmental effects on good audio gear is highly exaggerated. It is extremely easy to isolate a DAC from a power amp.
So back to the original premise, there are listeners who report vast differences in the items previously listed which are changes at the SOURCE only.
I've come to the conclusion that Lucy is the sanest of us all!
Today's Maserati's are not your father's Maserati's. Everything is microchip controlled, CAD designed and tested, and precision engineered. The times have changed.
Today's tube amps are also not your father's tube amps. Been running tubes for 8 years now with nothing but tube biasing once a year. Replaced several sets of tubes voluntarily.
Edits: 10/24/14
posting stuff without good basis or foundation.
If anyone wants a no tool method of mounting a CD Drive, fine but comparing this to a TEAC Neo owner and feeling sorry for him or her? This is a warped way of thinking.
I actually have 2 laser spares for my Krell with swing arm drive
I guess you don't remember the apodzing filters that were celebrated as the second coming of audio jesus...made knarly 80s CDs sound fresh remasters....
I thought you would get a kick out of the marketing tag line for the AMR 77 CD player:
"To bring compact disk playback back en par with the vinyl system."
Apodizing filters belong in the recording process. They do not belong in the playback process. If they were used in the recording process then many of the high frequency problems with Redbook playback would not be present. The problem is that recordings made properly with apodizing filters sound dull when played back with another round of apodizing filters, whereas recordings made with brick wall filters can (usually) be improved by playing them back with apodizing filters. This situation exists only because of the incompetence of Sony and Philips in specifying the Red Book standard. As a result, for best CD playback listeners have to select between a set of filters on a per recording basis, a situation akin to the early days of LPs, pre RIAA. (A few years ago, I simply gave up on tweaking filters. I just accepted the fact that no 44/16 digital recording could ever be considered to be high end and as such can never be a suitable reference for evaluating a playback chain. With CDs, one must simply accept their limitations and enjoy the music or else move on to better formats if the artists are still alive and recording with better technology.)
All of this is easy to verify by starting with a high resolution digital recording and downsampling it to Redbook with various filters and then playing it back with various filters. It can also be measured on spectrum plots or seen in impulse response plots. I speak from a fair amount of personal experience on this matter, as well as a fair amount of theoretical understanding. I have spent many hours experimenting with apodizing (and other) digital filters, measuring their performance and listening to how these filters affect sound quality. In each case, I started with a reference of how the particular recording was supposed to sound and the specific degradation imposed by the limitations of the 44/16 format and the conversion processes used (which were state of the art).
From a marketing perspective, the situation is obscured because of the variety of recordings and the variety of playback systems. Some playback systems start out too bright and in this case an apodizing filter serves as an upper treble "tone control", and in some cases multiple apodizing filters provide much needed high frequency roll-off. This is a characteristic of poor system setup, and has nothing to do with the digital filtering. These set up problems can be identified using high resolution digital recordings and corrected by appropriate measures, typically involving speaker placement, cross-over adjustments or room treatments.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
I agree about you that the filters belong in the recording procecs.
But around 2008 or 2009 when the sales of expensive CD players hit the skids, the manufacturers needed something to get people excited about and quite frankly they used clueless reviewers as stooges to spread the word.
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