[B] NEED HELP - Diganosing audio differences between source components [/B]

Ignoring that your testing methodology is seriously flawed, it's not unrealistic to assume that the levels from different sources inside of the Denon are not universally matched.

A properly controlled A/B test between two sources is fairly complex. You would have to ensure they are level matched, and perfectly synchronized to one another during playback. Then you'd have to blind yourself from them, and be able to switch between them to record your results. It would be a royal pain to set-up correctly. The goal is to remove external variables and sources of error.

See here for more:
https://en.wikipedia.org/wiki/ABX_test

General rule of thumb is that DA converters are equally transparent across the board - you aren't even changing DA converters in this scenario though. There's not going to be a "sound quality" variable that one player edges another in.

Honestly I'd just not worry about it - this is probably as simple as a level mismatch. Since you can't switch from A to B in real time (remember that auditory memory is only a few seconds), you really can't make any claims about what sounds like what - it's just not accurate. It may not even be a level mismatch, and instead simply a manifestation of perceptual bias (i.e. you know which is which, and that is influencing your choice).

Not identical. There will be measured differences between the two.


The Denon will convert the digital streams to analog. In both cases, it needs to extract the "clock" (incoming speed of the audio samples) to do that. And that differs between the two interfaces/equipment implementation. Both optical and HDMI tend to do worse in this regard than coax/S/PDIF and at any rate, will show differences in performance. That measured difference doesn't automatically result in audible difference.


You should definitely make a duplicate CD as long switch over time make the tests much less definitive.

For now, connect both optical and HDMI out of the Samsung. Then switch between them and see if you hear a difference. Alternatively test both players with optical. That way you can see if it is the interface or the player that makes a difference.

Okay. So that should be the logical end of the discussion (). But...


...there's a fly in the ointment (i.e. there's your bias).

To your first question: no. If you wanted to continue that argument, you'd need a metric to assess "accurate" and then a way to test it. What you're talking about occurs so "high up" in the chain that it's impossible to get at by playback time. Read: full tear-down and lots of time with a scope. However, this is a fool's errand, because we can just assume X and Y exist in a "black box" - if you can't pick them apart in a controlled A/B, you can't preference one, and it doesn't matter *how* they do what they do (so it could be a gnome and a pony in one, and buzzword compliant technology in the other).


To your second question: audiophile belief systems aside, yes. And to hit the corollary: regardless of connection type, yes (again, assuming levels are matched).

"Trust your ears" is not valid advice - even if you have two of the same CD, the lack of perfect synchronization between the two presents a real problem. It's not fun to test this correctly.

Anyways, the "gear sounds different" debate is a perrenial favorite, and you can take it up in other threads:
http://www.avsforum.com/avs-vb/showthread.php?t=1403349
http://www.avsforum.com/avs-vb/showthread.php?t=1100068

Because there are some really exceptional people out there with a great gift for prose who have been at this racket a lot longer than most of us.

Because the $9.99 Discman doesn't have an optical out. And it's probably made some major compromises on the analog end.

Change your question to a $50 DVD player and the answer is, because they're idiots. Seriously. High-end audio is a playground for know-nothings.

Yep. That'd be the best path.

It is all about how you do your listening.

The key words are:

(1) Level matched

(2) Time synched

(3) Quick switched

(4) Double blind.

Let me put it this way - if I do a listening test that does not deal with all 4 issues I can obtain perfect identification of the (non existent) differences between two identical music players. IOW I could compare two identical music players with different colored stickers on them, and tell you the color of the stickers.

OPPO has two popular players; the 93 and the 95. The digital-to-analog converters in the 93 are fairly good, but the ones in the 95 are higher accuracy converters, and the sound quality of the 95 is noticeably better as a result. That is just one example of why different players have different sound quality (and cost more).

The DAC chips in your old player are not only cheap, they are obsolete. The error rate on those things is crappy by current standards, and would only be used now on the very cheapest CD players. They were not even the best on the market 15 years ago. Surprise! It doesn't sound as good. Duhhhh.

Anyone who is silly enough to think that DAC conversion accuracy has not improved in the last 15 years is woefully unaware of the advances in DAC engineering that have taken place. This has a direct impact on sound quality, as any competent engineer is well aware. Those who insist on willful ignorance of the facts are always around, and easy to ignore.

The situation is similar to a digital camera; more pixels of resolution and a better quality lens equals better picture quality; but a person who looks at them through a dirty pair of glasses may not perceive the difference. A CD player with a better tracking accuracy and a more accurate DAC will give better sound quality, but if you are using a poor-quality amplifier and speakers, you may not hear the difference, even though the difference is certainly there.

Noticably better at doing what?


Error rate? Are you kidding me? Even cheap obsolete DACs have for all intents and purposes zero error rates.


Almost all of the significant sound quality improvements that have happened in DACs in the last 10-15 years have been improvements in price performance.

10 years ago we had DACs with 120 dB dynamic range, and high sample rates. They just cost thousands of dollars.

In terms of audible benefits in the home, there hasn't been a significant change since the middle 1980s, because that is when mainstream CD players starting having performance that was so good that built-in noise and distortion due to the acoustic and analog components in the recording process was so much higher.


If you use the best amps and speakers around, you will have the same problem. Been there done that, and this has been true since the middle 1980s.

"Masters, Ian G. and Clark, D. L., "Do All CD Players Sound the Same?", Stereo Review, pp.50-57 (January 1986)"


It appears that you have avoided contact with well-done listening tests.

It's quite amazing that you think that engineers have NOT been working on improving CD sound quality and DAC accuracy for the last 30 years, and that they have accomplished nothing. Complete ignorance of the extensive published documentation on the subject is apparent when you make these outrageous statements that are ludicrous on their face.

If you will simply read the many papers published by the Audio Engineering Society on this subject over the years, you will perhaps perceive how ludicrous your statements are (but of course I AM assuming you could understand something written by a competent engineer...we don't seem to have much indication that is the case).

It is quite revealing that you quote some yawps who published an opinion over 25 years ago on CD players to prove your case (and in a publication well-known for its lack of accuracy and validity). I guess that was the last time you seriously considered this subject; that's the way it seems.

Even IF those opinions had any validity then (highly unlikely), they certainly do not now!

It appears that you constantly avoid contact with anything real, scientific, or valid.



QUOTE-
Error rate? Are you kidding me? Even cheap obsolete DACs have for all intents and purposes zero error rates.

In terms of audible benefits in the home, there hasn't been a significant change since the middle 1980s, because that is when mainstream CD players starting having performance that was so good that built-in noise and distortion due to the acoustic and analog components in the recording process was so much higher.

"Masters, Ian G. and Clark, D. L., "Do All CD Players Sound the Same?", Stereo Review, pp.50-57 (January 1986)"

It appears that you have avoided contact with well-done listening tests.[/quote]

Most differences we hear between DACs are in fact differences between digital reconstruction filters. You can easily find this when you listen to a DAC where you canchoose one of several filters. With everything else the same (analog part and DAC chips themselves), you can hear profound differences in sound. In more simplier devices designers use filter provided by DAC chip itself (almost all chips have internal filter), so customer is at mercy of DAC chip manufacturer.

http://en.wikipedia.org/wiki/Non_seq...terary_device)

"A non sequitur ( /ˌnɒnˈsɛkwɨtər/; Latin for It does not follow) is a conversational and literary device, often used for comedic purposes. It is a comment that, because of its apparent lack of meaning relative to what preceded it, [1] seems absurd to the point of being humorous or confusing."

The reason why I suggest that your post is a non sequitur (joke?) because I didn't say that the engineers accomplished nothing, I said that they have made improvements in price performance. Actually, those improvements have been pretty dramatic.

Yes, but they are talking about improvements in the D/A portion.

Haven't you ever compared the spectra of a simple S/H dac output vs an 8 word-depth reconstruction filter?? The deeper the output math, the closer the output gets to the ideal. edit: invoking nyquist blindly without consideration of the depth is ill advised..

I'd recommend a good digital filter theory book for you, but mine is Papoulis, 1977..I'm sure the others could recommend a good refresher online..

j

News flash! Audio isn't about math, its about sound quality.

All you have to do is show evidence of the caliber provided by the cited article:

Masters, Ian G. and Clark, D. L., "Do All CD Players Sound the Same?", Stereo Review, pp.50-57 (January 1986)

conclusively showing that some modern optical disc player sounds better than the reference Sony ca. 1986 player that was used in that article.

Hmmm, 1986 was like 26 years ago. Should be easy!

HOLY MACKERAL...did you really just say that about digital reconstruction??I think I'll let the others bring you out of the stone age..

j

Do you have a theory as to why his levels would be different? And the method by which to equalize them if they are in his application?

Several of us have been trying for quite a while; he seems to be happy as a clam there. Lots of luck if you can penetrate that cave...rofl.

As a rule levels are different unless one goes out of one's way to match them. Why would nature be any other way?

The best means for obtaining matched levels varies with the application.

Again, no actual technical substance, just an insulting declaration.

Simple: OP's situation.

He has two digital transports feeding one AVR/DAC. One is using HDMI and the other Toslink. He has put the AVR in PURE DIRECT, turning off processing. What are the odds that AVR would try to change the levels of one digital source (Toslink) versus another (HDMI)?


Indeed and in this case, it would be a royal pain seeing how there is only one analog output from two digital sources.

Its not my job, its not the job of the tester to determine whether or not levels are matched by means of analysis, its the tester's job to take some simple measurements and ensure that the levels are matched.

Then there are the other issues I raised:


We now know that the listening tests up to this point failed the other 3 points - points 2-4.

Amir, why are you still going on and on, belaboring level matching? It's simple matter to settle with a few quick measurements using inexpensive and readily available equipment.

It is not any of our jobs to do anything here. But we try to be helpful. In this case, it is not helpful to send OP to chase unlikely causes.


All of those were already mentioned. Since you repeated the level match, I thought it was for a good reason. You are giving none so that is not the case it seems.


There is no "going on and on." Level matching is not likely to be OP's problem. If it were, you would have already explained why but you did not provide any. I am not lecturing OP here but trying to provide relevant things he can try that point to differentials in the two setups. I don't have the need to keep chanting slogans to belong to objecitivty camp if that is what you are asking .


If you were a betting man and had $100 to bet in Las Vegas, would you put odds on his levels being different or the same in this situation?

Quoted out of pure amusement.