Do I need clean USB power when using DAC with its own power supply?

[kumakuma]

7 minutes ago, fas42 said:

 

Since day one, over 35 years ago, of having capable playback I have had the problem of recordings sounding acceptable, or unacceptable, depending upon the 'tune' of the system

 

 

Perhaps it's a wetware problem...

[March Audio]

17 hours ago, Archimago said:

 

Tell me, what is this "digital noise" you speak of and what do you think "jitter" does when music is playing? Do you not think the "high frequency blur" will show up in testing?

 

Since some of these characteristics like the "blur", constricted sound stage are audible in your experience, can you hypothesize as to a test design that would differentiate DACs?

 

I think this is what bothers me.  There is often much hand waving about nebulous descriptors which are then attributed to nebulous things such as "digital noise" without any real definitions, evidence or correlation.

[fas42]

7 minutes ago, March Audio said:

Prat is just a made up term, it has no meaning.  

 

Just ask people to explain it and see how far you get.  If you take the actual meaning of the words then it makes little sense.

 

If you are concerned about pace, rhythm and timing, don't ever play an LP record with its inherent speed fluctuations which are massive compared to digital audio.

 

Lack of PRaT is very much a subjective sense of the music - it's comparable to an orchestra playing with no conviction, in a practice session, causing the conductor to start yelling at the musicians, wanting to kick their backsides - he knows the PRaT is bad; and has to shake them up, to lift the mood.

[fas42]

1 minute ago, kumakuma said:

 

Perhaps it's a wetware problem...

 

Which is why I said,

 

Quote

... people listen to playback with different mindsets; unless one is in the same room with the other person, hearing what's going on, then communication on the matter is always going to be difficult.

 

[March Audio]

1 minute ago, fas42 said:

 

Lack of PRaT is very much a subjective sense of the music - it's comparable to an orchestra playing with no conviction, in a practice session, causing the conductor to start yelling at the musicians, wanting to kick their backsides - he knows the PRaT is bad; and has to shake them up, to lift the mood.

I had to answer this even though I'm trying not to feed Frank.

 

How can you possibly compare a conductors function to that of a playback system?

 

All the things the conductor controls in an orchestra are fixed permanently in the recording.

 

Pace rhythm and timing are exceptionally tightly controlled in a digital system.

 

 

[Qhwoeprktiyns]

18 minutes ago, March Audio said:

Because the difference between low/high quality dacs is comparitvely small while between turntables its much larger.

 

When you read listening impressions on digital audio system configurations you would not think so! 

[fas42]

Just now, March Audio said:

I had to answer this even though I'm trying not to feed Frank.

 

How can you possibly compare a conductors function to that of a playback system?

 

All the things the conductor controls in an orchestra are fixed permanently in the recording.

 

Pace rhythm and timing are exceptionally tightly controlled in a digital system.

 

 

 

I'm talking of the subjective impression of the music one's hearing; not why it sounds like that - the conductor conveys a sense of urgency to his players, and they respond. Yes, the recorded performance of that is now permanent, but I most certainly have heard playback of some track where the sense of it is indeed that the musicians are "dragging their feet" - since I have heard the very same track full of life and vigor on other occasions, the fault must therefore lie with some aspect of the playback SQ.

[March Audio]

4 minutes ago, hopkins said:

 

When you read listening impressions on digital audio system configurations you would not think so! 

Aaahhhh.....but that's the inherent problem of uncontrolled subjective listening tests.

[kumakuma]

4 minutes ago, fas42 said:

 

I'm talking of the subjective impression of the music one's hearing; not why it sounds like that - the conductor conveys a sense of urgency to his players, and they respond. Yes, the recorded performance of that is now permanent, but I most certainly have heard playback of some track where the sense of it is indeed that the musicians are "dragging their feet" - since I have heard the very same track full of life and vigor on other occasions, the fault must therefore lie with some aspect of the playback SQ.

Aaahhhh.....the inherent problem of uncontrolled subjective listening tests.

[March Audio]

4 minutes ago, fas42 said:

 

it is indeed that the musicians are "dragging their feet" - since I have heard the very same track full of life and vigor on other occasions, the fault must therefore lie with some aspect of the playback SQ.

No Frank, the difference is in your head.  That's not meant to be rude BTW.  You just really need to recognise that your (mine) perception is not a constant.

 

If you did you might stop chasing your tail with all your pointless tweaks.

[Qhwoeprktiyns]

30 minutes ago, March Audio said:

Aaahhhh.....but that's the inherent problem of uncontrolled subjective listening tests.

 

Perhaps. But now think back about CD players. We had no trouble accepting the fact that a high quality CD player sounded better than a cheap one. We had explanations for this, (jitter being one of them). Now all of a sudden when it comes to computer based audio , we solve one issue (accuracy in extracting the data - provided a file is bit-perfect) but we trust that all other issues have been solved (jitter, noise)? Why? Probably because most DACs don't actually solve these issues, and because we don't fully understand them (and rely on a few amateurs running test tones and showing us nice graphs to demonstrate that DAC designers are all competent - most of these designers admitting themselves that they don't understand all that is going on!). . 

 

Unfortunately computer audio has solved some issues but has also created entirely new ones. 

[March Audio]

38 minutes ago, hopkins said:

 

Perhaps. But now think back about CD players. We had no trouble accepting the fact that a high quality CD player sounded better than a cheap one. We had explanations for this, (jitter being one of them). Now all of a sudden when it comes to computer based audio , we solve one issue (accuracy in extracting the data - provided a file is bit-perfect) but we trust that all other issues have been solved (jitter, noise)? Why? Probably because most DACs don't actually solve these issues, and because we don't fully understand them (and rely on a few amateurs running test tones and showing us nice graphs to demonstrate that DAC designers are all competent - most of these designers admitting themselves that they don't understand all that is going on!). . 

 

Unfortunately computer audio has solved some issues but has also created entirely new ones. 

Im afraid you are just generalising.  My anecdote.  I remember getting an ARcam Black Box (3 I think) and being hugely disappointed at just how little impact it had on sound quality over my existing (decidedly average) CD player.

 

I would present the issue in a slightly different way; that there is much assumption that issues are not solved, and regarding cause and effect.

 

 I go back to my previous comments. There is often much hand waving about nebulous descriptors which are then attributed to nebulous things such as "digital noise" without any real definitions, evidence or correlation.

 

If I show you a graph of jitter, showing very low levels, levels that have been demonstrated through controlled subjective listening tests to be inaudible, why would you continue to think that jitter is a problem?  Why would you think the designer doesnt understand the issue?  I appreciate that you just used jitter as an example, but it is one area that has been very well researched for many decades.  Here is a BBC paper from nearly 50 years ago on the subject.

Digital sound signals: Subjective effect of timing jitter - BBC R&D

[fas42]

45 minutes ago, March Audio said:

No Frank, the difference is in your head.  That's not meant to be rude BTW.  You just really need to recognise that your (mine) perception is not a constant.

 

If you did you might stop chasing your tail with all your pointless tweaks.

 

Alan, it's obvious that you need to live in a world where everything is neatly explained; especially when one can extract a neat set of numbers, and graphs, that tidy it all up. Unfortunately, reality conspires against us, all - and it has been thus since mankind first threw a bone or two in the air, 😄.

 

You just can't keep pushing everything uncomfortable away, and sweeping it under the "it's all in your head!" carpet ... extracting optimum audio playback is still very messy; that's the nature of the beast, to this day - tweaking is one of the best workarounds, until the whole industry develops a better understanding of how to control all the important factors.

[Qhwoeprktiyns]

25 minutes ago, March Audio said:

Im afraid you are just generalising.  My anecdote.  I remember getting an ARcam Black Box (3 I think) and being hugely disappointed at just how little impact it had on sound quality over my existing (decidedly average) CD player.

 

I would present the issue in a slightly different way; that there is much assumption that issues are not solved, and regarding cause and effect.

 

 I go back to my previous comments. There is often much hand waving about nebulous descriptors which are then attributed to nebulous things such as "digital noise" without any real definitions, evidence or correlation.

 

If I show you a graph of jitter, showing very low levels, levels that have been demonstrated through controlled subjective listening tests to be inaudible, why would you continue to think that jitter is a problem?

 

I don't claim to know what is a problem or not, but I do know what I hear. I also do know that there are still "unknowns"! Why, because the engineers manufacturing DACs often admit it. They themselves don't understand all that is going on. They admit that solutions are partial and imperfect. But they (mostly) all agree on the issues...

 

I trust their own admissions more than the few amateurs who publish blogs to explain the contrary. 

 

Vis à vis your jitter graph/tests:

 

There is no guarantee that jitter on a test tone will correlate with jitter levels on an actual music track. 

 

Controlled subjective listening tests could yield inconclusive results because the impact of jitter/noise is identical in all DACs sampled during those tests. 

 

All these so called "objective" measures and tests are simply a fad made popular by a few amateurs. The fact that some DAC manufacturers have jumped on the bandwagon and started offering products that "measure well" is just "noise". 

[March Audio]

14 minutes ago, hopkins said:

 

I don't claim to know what is a problem or not, but I do know what I hear. I also do know that there are still "unknowns"! Why, because the engineers manufacturing DACs often admit it. They themselves don't understand all that is going on. They admit that solutions are partial and imperfect. But they all agree on the issues... 

 

Concerning your other points:

 

There is no guarantee that jitter on a test tone will correlate with jitter levels on an actual music track. 

 

Controlled subjective listening tests could yield inconclusive results because the impact of jitter/noise is identical in all DACs sampled during those tests. 

 

 

 

You may well hear something, but why do you attribute it to a cause without any evidence?

 

With respect, your assumption that music is somehow different to a test tone when assessing jitter is incorrect.  Jitter is the variation in the dac word clock timing.  It is equally applicable to test tones as it is to music.  However with a steady test tone it allows the jitter levels and characteristics to be easily quantified where it cannot easily be done with variable music.

 

I dont know who or what you are referring to when you say "engineers/dac manufacturers admit it".

 

Can I suggest you read the BBC paper above.  Tests in that example were carried out by adding known quantities of jitter into the system.  Its not been tested in the way you imagine, but regardless, no 2 dacs have the same jitter characteristics.  Audibility thresholds have been well defined over many years of research.

 

[Qhwoeprktiyns]

Here is one example:https://www.hifi-advice.com/blog/specials/an-interview-with-raphael-pasche-of-ch-precision/

 

HFA: Do you know of a reason why Music Servers also differ in sound?

 

Raphael: I think the collective answer from the entire industry is that we don’t really know. Nobody knows exactly. Think back to when CD was first introduced. Audiophiles agreed that it didn’t sound very good in the beginning, but look how far we came and it’s pretty decent now. I think we will see a similar process for servers and streamers. There are just a few more things that collectively we have to do. We just have to eliminate layer for layer, what is causing the problem, and this takes time. We provide the receiver, the Renderer, and people can do what they like on the source side. We do get a lot of feedback from our customers, which gives us clues.

[March Audio]

8 minutes ago, hopkins said:

Here is one example:https://www.hifi-advice.com/blog/specials/an-interview-with-raphael-pasche-of-ch-precision/

 

HFA: Do you know of a reason why Music Servers also differ in sound?

 

Raphael: I think the collective answer from the entire industry is that we don’t really know. Nobody knows exactly. Think back to when CD was first introduced. Audiophiles agreed that it didn’t sound very good in the beginning, but look how far we came and it’s pretty decent now. I think we will see a similar process for servers and streamers. There are just a few more things that collectively we have to do. We just have to eliminate layer for layer, what is causing the problem, and this takes time. We provide the receiver, the Renderer, and people can do what they like on the source side. We do get a lot of feedback from our customers, which gives us clues.

I disagree with his comments and methods there. I can assure you he really doesnt speak for 'the entire industry".   Customer feed back is extremely unreliable due to the the varied nature of their systems and inherently uncontrolled nature of their comparisons.  Talking generically about CDs 30 years ago is a specious argument.

 

Also him saying "There are just a few more things that collectively we have to do" implies that he does understand the problems.

[Qhwoeprktiyns]

13 minutes ago, March Audio said:

 

You may well hear something, but why do you attribute it to a cause without any evidence?

 

With respect, your assumption that music is somehow different to a test tone when assessing jitter is incorrect.  Jitter is the variation in the dac word clock timing.  It is equally applicable to test tones as it is to music.  However with a steady test tone it allows the jitter levels and characteristics to be easily quantified where it cannot easily be done with variable music.

 

I dont know who or what you are referring to when you say "engineers/dac manufacturers admit it".

 

Can I suggest you read the BBC paper above.  Tests in that example were carried out by adding known quantities of jitter into the system.  Its not been tested in the way you imagine, but regardless, no 2 dacs have the same jitter characteristics.  Audibility thresholds have been well defined over many years of research.

 

 

If you look at a clock's specifications and take that as a measure of jitter then you are clearly missing out... 

[Qhwoeprktiyns]

2 minutes ago, March Audio said:

I disagree with his comments and methods there. He really doesnt speak for 'the entire industry".   Customer feed back is extremely unreliable due to the the varied nature of their systems and inherently uncontrolled nature of there comparisons.  Talking generically about CDs 30 years ago is a specious argument.

 

Also him saying "There are just a few more things that collectively we have to do" implies that he does understand the problems.

 

Wishful thinking. 

[March Audio]

Just now, hopkins said:

 

If you look at a clock's specifications and take that as a measure of jitter then you are clearly missing out... 

I agree. Who is doing that?

 

You absolutely must measure the dac output. You then correlate  subjectively with what people hear.

[March Audio]

1 minute ago, hopkins said:

 

Wishful thinking. 

A conclusion based on what evidence?

[Qhwoeprktiyns]

Just now, March Audio said:

I agree. Who is doing that?

 

You absolutely must measure the dac output. You then correlate  subjectively with what people hear.

 

Good luck doing that with an actual track...

[March Audio]

1 minute ago, hopkins said:

 

Good luck doing that with an actual track...

Its actually very simple.  You add known quantities of jitter into a system and see at what points listeners find it audible.  The levels are surprisingly high compared to what most DACs achieve these days.

[Qhwoeprktiyns]

6 minutes ago, March Audio said:

Also him saying "There are just a few more things that collectively we have to do" implies that he does understand the problems.

 

This is wishful thinking on your part. 

[Rexp]

4 minutes ago, March Audio said:

I agree. Who is doing that?

 

You absolutely must measure the dac output. You then correlate  subjectively with what people hear.

You still don't get it, there are no measurements that correlate with the listening experience. You science guys have failed to develop the appropriate tech.