Jitter at DSD rates

[Siltech817]

On 4/6/2020 at 4:55 PM, Miska said:

 

Typically problems are caused by interference on the clock lines, where some external interference signals are modulating the clock.

 

 

Including for example physical vibration/resonance, no?

[pkane2001]

10 hours ago, Siltech817 said:

 

Including for example physical vibration/resonance, no?

 

Do you have your DAC sitting on top of a subwoofer? 

[Siltech817]

1 hour ago, pkane2001 said:

 

Do you have your DAC sitting on top of a subwoofer? 

Of course not, however I was not only referring to airborne vibration, this can even be a function of the power supply, or the resonant characteristics of certain capacitors or other elements in the circuit including the placement of the oscillator itself, and the overall layout of the board.

Since everything is built to a price point, not all will be created equal with regard to careful attention paid and budget allowed for this element of the design. Not a one size fits all answer, and yes it's audible, and no I don't have any sophisticated measurement equipment, nor do I feel compelled to provide any ABX testing results.

Place a DAC on different kinds of footers, shelves, racks, etc... made from different materials. It does not all sound the same. Neither do all different DSD capable DACs sound the same, and this is likely one reason or contributing factor as to why, unless you think jitter is fake news or something like that. TI for example does not.

It's not crazy to think this sort of thing can be audible, though because the audio industry has never agreed to a set of criteria for what and how to measure jitter, and then proven what is audible and what is not, it's silly for anyone to get up on a soapbox and suggest they know everything there is to know about it, or that the only issue would be if one were so stupid as to place a DAC on top of a subwoofer.

snaa296.pdf

[jabbr]

3 hours ago, Siltech817 said:

It's not crazy to think this sort of thing can be audible, though because the audio industry has never agreed to a set of criteria for what and how to measure jitter, and then proven what is audible and what is not, it's silly for anyone to get up on a soapbox and suggest they know everything there is to know about it, or that the only issue would be if one were so stupid as to place a DAC on top of a subwoofer.

 

I post this article frequently:

https://www.sitime.com/company/news/blog/what-you-need-know-about-phase-noise-and-jitter-high-speed-systems

(it demonstrates that certain clock oscillators are vibration sensitive)

 

Ok so we know this ... but hmm what is the effect of jitter in the 11 or 22 Mhz DAC clock (DSD256/DSD512) on the DAC output? Clocks are pretty good these days ... so while it most certainly isn't crazy to think that jitter is audible, there is a limit to what might be audible i.e. how many dB down can you hear anything? 

[pkane2001]

7 hours ago, Siltech817 said:

Of course not, however I was not only referring to airborne vibration, this can even be a function of the power supply, or the resonant characteristics of certain capacitors or other elements in the circuit including the placement of the oscillator itself, and the overall layout of the board.

Since everything is built to a price point, not all will be created equal with regard to careful attention paid and budget allowed for this element of the design. Not a one size fits all answer, and yes it's audible, and no I don't have any sophisticated measurement equipment, nor do I feel compelled to provide any ABX testing results.

Place a DAC on different kinds of footers, shelves, racks, etc... made from different materials. It does not all sound the same. Neither do all different DSD capable DACs sound the same, and this is likely one reason or contributing factor as to why, unless you think jitter is fake news or something like that. TI for example does not.

It's not crazy to think this sort of thing can be audible, though because the audio industry has never agreed to a set of criteria for what and how to measure jitter, and then proven what is audible and what is not, it's silly for anyone to get up on a soapbox and suggest they know everything there is to know about it, or that the only issue would be if one were so stupid as to place a DAC on top of a subwoofer.

snaa296.pdf 2.77 MB · 5 downloads

 

So the paper used 4g acceleration for sine vibration, 7.5g for random, and 500g for shock. I would hope you don't normally experience these levels anywhere near your DAC... But, if you do, then there may be some added jitter. This would place your listening room conditions to be somewhere between a jet airplane and boost stage of a missile:

 

 

 

[Siltech817]

3 hours ago, pkane2001 said:

 

So the paper used 4g acceleration for sine vibration, 7.5g for random, and 500g for shock. I would hope you don't normally experience these levels anywhere near your DAC... But, if you do, then there may be some added jitter. This would place your listening room conditions to be somewhere between a jet airplane and boost stage of a missile:

 

 

 

Again, SO WHAT? 

You read the TI brief correctly of course, but that in no way means that you have solid verifiable evidence that vibration or resonance at lower levels, including that which is not airborne, bears no audible effect on audio systems.

You don't know that, and I can tell that either you've never ever tried what I described with using footers of differing materials, shelving, racks etc... under DACs (or any other audio component for that matter) or, if you did, your expectation bias (that is: you already know all there is to know about this) fully prevented you from hearing any differences.

Note I make no claim as to the exact magnitude of such a difference, nor make any claim that one can equate that difference with any particular cost delta in an exacting manner. To each their own on the cost delta.

Did your subwoofer as component support example actually prove anything relative to the paper I attached? I thought according to your post this was only an issue of jet engine type vibration, or rocket launch type vibration? Now only vibration from a subwoofer can create an audible difference in the realm of audio systems? Really? At what SPL must we have the sub's output before a problem can occur?

So you know this to be the case then, and all assertion to the contrary can easily be refuted with detailed measurements as provided by who, the "science" site?

I think not.

BTW - I see you fully skipped the part about board layout, resonant characteristics of capacitors chosen, or the power supply proximity. Shall we include EMI/RFI fields as well? Thermal influence too?

[Siltech817]

6 hours ago, jabbr said:

 

I post this article frequently:

https://www.sitime.com/company/news/blog/what-you-need-know-about-phase-noise-and-jitter-high-speed-systems

(it demonstrates that certain clock oscillators are vibration sensitive)

 

Ok so we know this ... but hmm what is the effect of jitter in the 11 or 22 Mhz DAC clock (DSD256/DSD512) on the DAC output? Clocks are pretty good these days ... so while it most certainly isn't crazy to think that jitter is audible, there is a limit to what might be audible i.e. how many dB down can you hear anything? 

Thank you for that link, very interesting for sure.

My point is that neither pkane2001, nor anyone else, possesses any absolute proof as to what is audible in this realm and what is not, and until such time as the actual measurement method and means are agreed upon and standardized, he is pissing in the wind, and needs to get down off that soapbox.

Subwoofer or rocket launch, which one is it?

Power supply architecture, choice of capacitor type, and board size/layout, only trivial?

We know not.

What about EMI/RFI, might we consider that as a form of vibration or resonance in terms of its actual effect or influence on audio circuits?

 

 

[pkane2001]

5 hours ago, Siltech817 said:

Again, SO WHAT? 

You read the TI brief correctly of course, but that in no way means that you have solid verifiable evidence that vibration or resonance at lower levels, including that which is not airborne, bears no audible effect on audio systems.

You don't know that, and I can tell that either you've never ever tried what I described with using footers of differing materials, shelving, racks etc... under DACs (or any other audio component for that matter) or, if you did, your expectation bias (that is: you already know all there is to know about this) fully prevented you from hearing any differences.

Note I make no claim as to the exact magnitude of such a difference, nor make any claim that one can equate that difference with any particular cost delta in an exacting manner. To each their own on the cost delta.

Did your subwoofer as component support example actually prove anything relative to the paper I attached? I thought according to your post this was only an issue of jet engine type vibration, or rocket launch type vibration? Now only vibration from a subwoofer can create an audible difference in the realm of audio systems? Really? At what SPL must we have the sub's output before a problem can occur?

So you know this to be the case then, and all assertion to the contrary can easily be refuted with detailed measurements as provided by who, the "science" site?

I think not.

BTW - I see you fully skipped the part about board layout, resonant characteristics of capacitors chosen, or the power supply proximity. Shall we include EMI/RFI fields as well? Thermal influence too?

 

Wow, buddy. You are putting so many words in my mouth, I'm starting to choke. Did I claim any absolutes? Did I state that only vibration from a subwoofer can cause jitter? Did I assert anything at all, except to provide an interpretation of the paper you posted, which is perfectly consistent with the study conducted?

 

How about, instead of you telling me that I can't possibly know everything (hint: I don't), or telling me that I can't prove a negative (hint: I can't) you provide an objective evidence that you can hear the effects of a crystal vibration due to the speaker sound in your listening room (hint: you can, but only if you want to).

 

Oh, and why do you bring in EMI/RFI or thermal effects that are not related to the simple physical shock and vibration? I made no statements about these.

 

5 hours ago, Siltech817 said:

My point is that neither pkane2001, nor anyone else, possesses any absolute proof as to what is audible

 

Only a Sith Deals in Absolutes. And I'm no Sith 😜

[jabbr]

6 hours ago, Siltech817 said:

My point is that neither pkane2001, nor anyone else, possesses any absolute proof as to what is audible in this realm and what is not, and until such time as the actual measurement method and means are agreed upon and standardized, he is pissing in the wind, and needs to get down off that soapbox.

 

This thread, as I understand it, isn't about the entire realm of audibility.

 

Its about the effects of jitter on audio encoded as DSD (single bit SDM).

 

I have suggested that upsampling DSD *decreases* the effects of jitter on the 20kHz and under audio carried by the bitstream.

 

We aren't talking about whether anything else is audible, nor is anyone saying that jitter doesn't exist, or any other common form of noise for that matter, yet since we have good experience that voltage noise at, for example, -140dB below the signal, isn't audible, we can discuss what the lower limits of phase noise audibility are as well.

[Siltech817]

9 hours ago, pkane2001 said:

Did I claim any absolutes? Did I state that only vibration from a subwoofer can cause jitter?

You made a condescending and jerky reply to a post I made that was not directed at you, rather it was directed at Miska, and it said exactly this:

 

On 4/19/2020 at 2:13 AM, Siltech817 said:

Including for example physical vibration/resonance, no?

 

I asked him a question, somehow that generated your rude subwoofer comment, perhaps I should have played along and asked you if that were the only such condition we should be concerned with, but you knew what you were inferring, or you wouldn't have said it. Then the follow on:

 

18 hours ago, pkane2001 said:

I would hope you don't normally experience these levels anywhere near your DAC... But, if you do, then there may be some added jitter. 

 

More condescending sarcasm, but hardly surprising, I've seen this act before.

 

9 hours ago, jabbr said:

 

We aren't talking about whether anything else is audible, nor is anyone saying that jitter doesn't exist, or any other common form of noise for that matter, yet since we have good experience that voltage noise at, for example, -140dB below the signal, isn't audible, we can discuss what the lower limits of phase noise audibility are as well

 

Perhaps I did misunderstand the purpose of the thread, I apologize for asking a simple question about whether or not we can consider including the effects of vibration and resonance on jitter at DSD rates. Evidently the OP found reason to launch into condescending sarcasm and mockery as the reply. I'll take his answer as reason not to set my DAC on a subwoofer and call it a day.

 

 

 

[jabbr]

12 minutes ago, Siltech817 said:

Perhaps I did misunderstand the purpose of the thread, I apologize for asking a simple question about whether or not we can consider including the effects of vibration and resonance on jitter at DSD rates. Evidently the OP found reason to launch into condescending sarcasm and mockery as the reply. I'll take his answer as reason not to set my DAC on a subwoofer and call it a day.

 

As the paper demonstrates, there are ways to significantly mitigate the effects of both vibration and PSU sensitivity on clock oscillator phase noise -- you are correct that both of these are factors. 

[pkane2001]

28 minutes ago, Siltech817 said:

You made a condescending and jerky reply to a post I made that was not directed at you, rather it was directed at Miska, and it said exactly this:

 

 

I asked him a question, somehow that generated your rude subwoofer comment, perhaps I should have played along and asked you if that were the only such condition we should be concerned with, but you knew what you were inferring, or you wouldn't have said it. Then the follow on:

 

 

More condescending sarcasm, but hardly surprising, I've seen this act before.

 

 

Perhaps I did misunderstand the purpose of the thread, I apologize for asking a simple question about whether or not we can consider including the effects of vibration and resonance on jitter at DSD rates. Evidently the OP found reason to launch into condescending sarcasm and mockery as the reply. I'll take his answer as reason not to set my DAC on a subwoofer and call it a day.

 

 

I'll chalk this up to you having a bad day. You misinterpreted a very short question I asked you, proceeded to read into it something I didn't say or mean to say, and then went on a tirade. Please, stay out of this thread until you can communicate in a civil fashion and without the insults. @The Computer Audiophile, please give me moderator rights.

[The Computer Audiophile]

4 minutes ago, pkane2001 said:

please give me moderator rights.

Done.