How to improve Jitter issue via USB/ETHERNET ?

[thumb5]

You're welcome to your opinion, of course, but given that there are strong and easily-understood reasons why clock/inter-sample jitter should not be the cause of sound quality differences between USB cables, the onus is on you to explain how you "know" it's jitter in some objective way. For example, what experiments have you done to measure jitter (whatever you take that to mean in this context) and correlate it with the sound differences? Can you for example rank a number of USB cables in terms of increasing "jitter" in such a way that someone else could independently measure the same results? How exactly do you propose to measure this "jitter", even in principle? If you can't answer those questions, I'd argue you're not really talking about jitter, which is a well-defined, objective, engineering term - rather you're just saying which cable you think sounds best and arbitrarily attaching the word "jitter" to it with no real justification.

Just to be perfectly clear, I'm not arguing that you (personally) can't hear differences between cables - that's entirely up to you.

[yabaVR]

You're welcome to your opinion, of course, but given that there are strong and easily-understood reasons why clock/inter-sample jitter should not be the cause of sound quality differences between USB cables, the onus is on you to explain how you "know" it's jitter in some objective way.  For example, what experiments have you done to measure jitter (whatever you take that to mean in this context) and correlate it with the sound differences?  Can you for example rank a number of USB cables in terms of increasing "jitter" in such a way that someone else could independently measure the same results?  How exactly do you propose to measure this "jitter", even in principle?  If you can't answer those questions, I'd argue you're not really talking about jitter, which is a well-defined, objective, engineering term - rather you're just saying which cable you think sounds best and arbitrarily attaching the word "jitter" to it with no real justification.

Just to be perfectly clear, I'm not arguing that you (personally) can't hear differences between cables - that's entirely up to you.

No, I've not made measurements of any USB cable. I have listened to many and compared them. I also listened to many AES/EBU cables and SPDIF in my business. For me all this startet 30y ago at first mainly in the analogue realm. Variations in sound with analogue cables are completely different compared to digital cables. You get used to these differences over the years. What I actually mean...you hear it. Yes, you can hear the sound texture of more or less jitter in an audio system and in cables. I know this proofs nothing to others espacially not to the measurement party.
If it helps...I don't want to tie it down on this jitter issue. Maybe there's something else in the game. But no doubt there is something and it is objective.
I just want to share my experiences and help others to trust in what they're experiencing with this stuff. You don't make this up and you're not fooling yourself. It's there.

@thumb5
Have you ever made an AB (ABX) of several different USB cables or any other cables. Was it with a high resolving/transparent system or just a MAC book USB to any DAC comparison.
What's your conclusion. I'd like to have a statement of yours based on experience not only a measurement argument and textbook justification. If you heard differences what do you think is the cause (other than psychoacoustic/expectation bias...please)?
Or did you never hear any difference in cable ABs?


gui

[thumb5]

Gui, as I said earlier, I don't think you're making up the fact that you hear differences - and I hope I didn't give that impression.  I do feel that ascribing what you hear to jitter is misleading unless you have objective evidence that jitter in the specific, technical sense is truly the cause.  To put it more clearly, you could replace the word "jitter" in your previous post with the word "badness" and (I believe) it would not change what you're actually communicating to anyone else.

Actually I don't think whether or not I can hear differences between cables is relevant, for these reasons: firstly, I haven't argued that I can hear such differences, and secondly, if I were to hear any I feel that the most likely cause (at least for me) would be due to what's subjectively going on in my head rather than what's objectively happening in the cable.  Thirdly, I prefer not to get into "my ears/system are better than your ears/system" discussions.

Since you asked my opinion on the topic: I believe that there may be cases where cables can make a difference, depending on the interface and the specific devices at each end.  From what I've read the most likely objective, potential causes of sound quality differences in USB and Ethernet cables seem to be things like noise transmission, ground currents and possibly EMI/RFI.  These effects are probably so sensitive to the exact system set-up that what works well in one system will not work well in another, so it's more or less impossible to generalise from any individual experience.

However, this sounds like digging rather hard to find something to pin a sound quality difference upon.  If the difference is repeatable in a well-designed test then that might be justified, of course.  But I don't think it's necessary to resort to anything as esoteric as that when there's only anecdotal evidence or a sighted AB comparison.

You seem determined to keep psychoacoustics and expectation bias out of the discussion, but it can't be eliminated from the normal experience of listening (that is, outside a properly-designed experiment).  Our hearing is very easily fooled; just to pick one example, the McGurk effect shows how hearing can tell us quite different things depending on what we see.  This effect is not subtle, and it is very strong even when you know about it - it's just the way the brain works, like it or not.

[yabaVR]

Hey thumb5,
I'm not determined to not believe in psychoacoustics and expectation bias. I deal with this every time I do ABs or try out new things. Some times the first impression might be false and other (most) times it's right. The thing I don't want to discuss about psychoacoustics and expectation bias is that these arguments are so blunt and worn to me but only count for a very small percentage in my experience. I klicked the link and did the test in the video. I can confirm that it's valid but I have to say I only read the first line of the text and then viewed the video. I immediately felt that something was wrong with the presentation of this woman's voice. It was disturbing. Then I read the text and did the test again and yes I can confirm the test. It just tells me that my brain can be deceived when my eyes AND my ears are giving different perceptions at the SAME time. But this effect at least for me is not related to ABs in HiFi audio.
It's my habit to listen to music eyes closed and for me a difference in sound while doing an AB is apparend from 1s -5s at the beginning or the resume of a song. And it's so easy because the differences are quiet big with cables. Differences are smaller with e.g. upsampling or software updates (for audio) or digital filters and the like. I misleaded myself one time or another with that. But you get the wrong things right in long time listening sessions.

It's not my purpose to be right on the things I say. But as I know the sound texture of jitter well and I can hear this texture when comparing digital cables (synchronouds & asynchronous). My best guess is that the difference is due to jitter. Now, it could be anything else I (we) don't know of and you can call it 'badness'. I call it what comes next to my empirical knowledge.
So no fight and no 'my ears are better than yours'. Peace.

gui

p.s. For me the test by the link confirms that my eyes can easily be fooled but my hearing tells me the truth when my eyes are closed. Our ears are by far the most sensitive sense we have and for that can be trusted the most. No doubt though that the perception of the material world is all made up in our brain.

[thumb5]

Thanks for your reply Gui. I don't think we're ever likely to agree on this, but it's been an interesting discussion.

[thumb5]

For reference, here's an interesting thread from the Roon forum: https://community.roonlabs.com/t/raat-an...rship/6915, originally linked by @Confused in his streaming set-up thread.

Brian Luczkiewicz's (Roon) clear and comprehensive explanations in posts 38 and 41 of that thread and Andrew P's (of dCS) in posts 48 and 53 should be "required reading".

[Jean-Marie]

For reference, here's an interesting thread from the Roon forum: https://community.roonlabs.com/t/raat-an...rship/6915, originally linked by @Confused in his streaming set-up thread.

Brian Luczkiewicz's (Roon) clear and comprehensive explanations in posts 38 and 41 of that thread and Andrew P's (of dCS) in posts 48 and 53 should be "required reading".

Very interesting and documenting very well why in a properly engineered system, the DAC clock is the only one that can affect SQ in a different manner than just skipping or shuttering. 

Jean-Marie

[Celts88]

For reference, here's an interesting thread from the Roon forum: https://community.roonlabs.com/t/raat-an...rship/6915, originally linked by @Confused in his streaming set-up thread.

Brian Luczkiewicz's (Roon) clear and comprehensive explanations in posts 38 and 41 of that thread and Andrew P's (of dCS) in posts 48 and 53 should be "required reading".

Very interesting and documenting very well why in a properly engineered system, the DAC clock is the only one that can affect SQ in a different manner than just skipping or shuttering. 

Jean-Marie

Jean-Marie

Would the new Clock (or whatever it is inside the Core Infinity) now have overall impact on the SQ being produced by the upgraded Pro's?

A reply I previously had from Devialet in regards to the CI and Clock was:

"The Core Infinity board will effectively be the one to generate and distribute the purest clock signals, including the word clock. Those signals are then rerouted on the motherboard."

Cheers
John

[Jean-Marie]

Yes, the CI clock is the clock driving the DAC, hence the possible improvement.

Jean-Marie

[PeppaPig]

Bits are bits: there, I've said it.  But I will wager that has nothing to do with the kind of sound quality differences that @Confused has been talking about recently: I trust @Confused would agree they are subtle and not caused by drop-outs due to bit errors.  Over USB or Ethernet, any errored bit will cause drop-out that should be clearly audible, unless Devialet have deliberately engineered their USB and Ethernet hardware and drivers to do something different.  So if there is a sound quality difference it is not caused by "bits not being bits".  There are plenty of proposed mechanisms for such differences, but I'd say the most plausible are in the analog domain.

For example, could it not be that the sound quality differences are caused by subtle differences in grounding, noise injection, etc. that would vary with the number and type of boxes connected, and the cables between them (more or less independently of what the boxes are doing in the digital domain)?  That would explain, without resort to expectation bias, why there's always a change to be heard when changing equipment.  Just because it's "digital" audio doesn't mean these kind of analogue effects are ruled out -- far from it, they may become relatively more significant because they are not masked by higher levels of noise and distortion that would be present in an analogue signal.

Yes, I would agree that the differences I am referring to are not caused by drop-outs due to bit errors.  Noise, grounding and 'leakage loops' are certainly factors.  Although I would say the difference in treble I mentioned is somewhere in the rage between subtle and easily audible, this is what really fascinates me.  I would say it is at a level that could be measured with REW or similar.  I would try this, but the only way to run REW is via AIR or USB.  If anyone out there knows a straightforward way to run REW via a microRendu, then I would be happy to try this objectively, but it is not possible as far as I am aware.   

So, back to the OP's question about jitter.  The first point I would make is that I do not think 'zero jitter' is possible, even the very best audio clocks in the world produce jitter, albeit at fantastically low levels.  Many would argue that modern well engineered digital audio systems have now reduced jitter to levels that are not audible, so it is no longer an issue.  The Devialet's Ethernet and USB inputs use asynchronous protocols, so in simple terms the Devialet's clock is in charge, it is a very low jitter clock, so this is a non issue.

Others are going beyond this, claiming that decent clocks in audio systems reduce noise, (or bad clocks increase it) and that improving the 'clocking' on a USB feed can improve sound quality.  This is a very controversial area, John Swenson (UptoneAudio / Sonore designer) is currently doing some testing in this area, apparently he has put together some unique test equipment to do this.  He has been doing this for a few months now with no sign of him producing any results.  It should also be remembered that digital audio systems need multiple clocks.

This subject has been debated extensively elsewhere, and often includes the statement that there are effects in digital audio due to mechanisms 'not yet fully understood'.  I tend to think this is true, although it is a rather week statement, after all, the 1's and 0's appear to be more than capable of running aircraft autopilot systems, industrial control systems, the internet, space missions, medical scanners, and this kind of stuff.  it's just digital audio that has not yet fully understood these 1' and 0's.

Hi Confused, you said the Devialet internal clock is a very low jitter clock, is that means if I use Mac mini USB into Devialet’s USB, I don’t need Mutec MC-3 in the middle as there is no benefit?