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Blue or red pill?


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3 hours ago, adamdea said:

 

You could, with equal or greater validity, pose the question “is it possible to design a dac so badly that its output varies audibly according to the non-information properties of the input data? And you may (but only may) have answered that question.

 

I prefer the term "robust", rather than "isolation" - will the system, moving beyond component behaviour, always "sound the same" no matter what is happening in its environment? IME, this is extremely difficult to achieve - a combination of the sensitivity of the human hearing system to subtle anomalies, and the way audio systems are put together.

 

IOW, "all DACs are badly designed" ... IME, it's trivially easy to do something relatively innocuous in the electrical surroundings of an audio system, which causes the sound to change - just because standard measurements pick up nothing abnormal is meaningless - "you're not measuring the right things!".

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41 minutes ago, jabbr said:

My definition of “isolation” is hardly circular. My intention of providing a definition is so that the term “isolation” can be meaningfully used in discussion — that’s my intent. Do you have a different definition? Please tell?

 

It’s circular in this sense (or perhaps iterative would be more apt?)...

 

What constitutes a dac?

 

As designers are becoming more creative in finding ways to “improve” (isolate?) the signal sent to the dac (rendu, regen, lush cable, whatever) it would reasonably follow that if accepted these concepts work, they may in future all be incorporated into one box; presumably still a dac. 

 

Not contrary to to your definition but maybe moving the goalposts.

 

So Damien and Peter have to up their game(s) and refine their software to justify their existence. They succeed, differences are audible once more, John Swenson or whoever comes up trumps, new product and isolates them again...

 

...and so it goes

 

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6 hours ago, jabbr said:

To me, by definition, “isolation” means that the DAC is not affected either sonically or electrically by vagarities in otherwise identical or not identical bit perfect streams ?

 

If a DAC were perfectly isolated, I'd agree.

 

6 hours ago, jabbr said:

What does “isolation” mean to you?

 

We first need to answer the question, "Isolation from what?" And we can't answer this until we've fully articulated the exact mechanism that causes different jitter signatures with bit-identical replay.

 

Mani.

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15 hours ago, manisandher said:

 

I think we can all agree that the Altmann is not a particularly good-measuring DAC, based as it is on the late '80s1543 chip. The key question is: did this compromise the A/B/X in any way? I'd say absolutely not.

 

My understanding, from a research perspective, would be the DAC may have altered the sound in that it is a variable in the test methodology. However, it is a controlled variable in that the exact same DAC was used for the A/B/X hence it should not compromise the experiment in any way. This can only be said IF it is agreed that the experiment was about bit identical streams sounding differently in playback. Obviously the DAC could respond differently to non-bitstream data or in other ways not related to the bits being identical, and therefore perhaps explain the audible differences. The latter however would strengthen rejecting the null hypothesis, not compromise it (null hypothesis = it is not possible for bit identical playback to sound different)

 

15 hours ago, pkane2001 said:

 

 But, that lack of jitter rejection or other issues within your DAC  could have caused you to hear a difference, where a better DAC or a USB reclocking interface would eliminate them, I’m afraid you didn’t test for at all.

 

This is why I said... "This.... [the same DAC used for ABX does not compromise the experiment].... can only be said IF it is agreed that the experiment was about bit identical streams sounding differently in playback". The *reasons* for the observed difference,"a better DAC or a USB reclocking interface" or whatever is subject to further testing/inquiry.

 

14 hours ago, adamdea said:

The problem with ABXXXXXXXXXX is that after the first attempt, if one is thinking back to AB then it's too long ago.  Unless one thinks "is X(n )the same or different to X(n-1)",  one is likely to go astray (I think that's probably the only way of doing it within audio memory) . And once you get one wrong the next few choices will go wrong too.

 

+1, too many false positives and false negatives with ABXXXXXXXX which will very likely descend into pure guesswork.

 

 

14 hours ago, adamdea said:

The other thing is that if there is an unconscious switching tell then it might take a while to learn (I know it 's a bit weird to talk about learning something subconsciously). 

My guess is that the 4/10s are probably random.

 

IMO not weird at all that there might be a learning effect but IF the same switching mechanism was used throughout, one would have to say that variable was controlled.Sure, I know that in the universe of all possible things anything is possible but, as I see it, it is reasonable to believe that variable has been reasonably covered subject to evidence to the contrary.......Good luck on HA btw!

 

 

7 hours ago, jabbr said:

 

Of course the results are DAC dependent. Too much focus here on the DAC IMHO. The test was supposed to show that so-called bit identical streams can have measurablely different SQ. It has and repeating test can increase certainty of this.Next step is to ascertain why and under what circumstances. One would expect that as input isolation improves, these SQ differences decrease.

 

1+

 

6 hours ago, manisandher said:

 

In my experience, this is not the case. The Phasure NOS1 DAC is better isolated than any other DAC I'm aware of, and yet it is still massively affected by these sorts of bit-identical changes.

 

 

seems counter-intuitive

 

 

53 minutes ago, jabbr said:

A perfectly isolated DAC, according to my understanding of the term “isolated”, will have the same sound regardless of electrical differences in the “bit identical” incoming bitstream — eg a regen or other isolating device, would, if the DAC were perfectly isolated, not make a difference in SQ.

 

that sounds logical.

 

Sound Minds Mind Sound

 

 

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40 minutes ago, manisandher said:

 

If a DAC were perfectly isolated, I'd agree.

 

 

We first need to answer the question, "Isolation from what?" And we can't answer this until we've fully articulated the exact mechanism that causes different jitter signatures with bit-identical replay.

 

Mani.

 

Mani, there are further tests that can help pinpoint the source of the audible difference.

 

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7 hours ago, manisandher said:

For anyone coming in late to this thread, the red and blue lines in Mans's plots above are captures of the DAC's analogue outputs being fed two bit-identical data streams.

 

Can someone give a proper definition for bit-identical data, please? My understanding is when we say something is bit identical that means it does not include any other code of the sender along with the original bits. In Tascam, the SFS was probably ignored when the data were captured. In the case of DAC, although it received bit-identical data it also had received variable in the form of SFS which could have handled and processed differently. 

 

The use of bit-identical term to be included in the explanation of the audible difference is IMO may confuse the issue further.

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2 hours ago, manisandher said:

We first need to answer the question, "Isolation from what?" And we can't answer this until we've fully articulated the exact mechanism that causes different jitter signatures with bit-identical replay.

 

 

In this context isolation from effects on SQ arising from other than the bit stream

 

Again, isolation implies that two identical bitstream will sound and measure the same at the output of the DAC.

 

The better the isolation, the less the difference in both SQ and any measurable effects.

 

@PeterSt indicates that SFS affects “jitter” yet I haven’t seen an appropriate measurement that demonstrates this. One could for example provide a phase error plot at the carrier frequency of the bitstream. (this applies to a clocked bitstream not only a clock)

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2 hours ago, manisandher said:

If a DAC were perfectly isolated, I'd agree.

Good. One would expect that as the isolation alone becomes better that the SQ differences would decrease.

 

That said two different DACs may have different SQ responses to SFS that are not entirely due to isolation ie if one DAC is “more resolving” it might unmask subtle SQ effects that the other DAC dies not reveal — I’m granting this — nonetheless for any given DAC, as isolation improves, effects such as input jitter become less apparent — by definition ?

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5 minutes ago, acg said:

Better isolation for sure,  lower noise floor,  a bit or so of extra resolution and better SQ but something that did not matter before now matters... and SFS changes if anything are more audible. 

 

Go figure!

 

A key Law of Audio applies, in all situations ... the closer one is to hearing the raw state of the recording, the more everything one does will have an audible impact. There is no way around this - at some point decide that you're "close enough" ... and, be happy ... :D.

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3 hours ago, Audiophile Neuroscience said:
11 hours ago, manisandher said:

 

In my experience, this is not the case. The Phasure NOS1 DAC is better isolated than any other DAC I'm aware of, and yet it is still massively affected by these sorts of bit-identical changes.

 

 

seems counter-intuitive

 

The more galvanic isolation, the better the effects become audible. But someone just said it : the playback quality got better all over (say lower noise) and with the strength of the effect remaining the same, it thus becomes better audible. This is empirically found theory after the real life experience of the happening(s).

 

I have said numerous times that we must look at the backdoors here. Thus not the interface but all else.

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4 hours ago, Audiophile Neuroscience said:

eg a regen or other isolating device, would, if the DAC were perfectly isolated, not make a difference in SQ.

 

@jabbr, I am sure this makes sense to you, but not to me. It is high time that you describe your meaning of "isolated". Try to avoid the figurative speak now, because that doesn't help in understanding. It may also point you at not legitimate recursiveness (see, I can do it too O.o).

 

 

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1 hour ago, jabbr said:

@PeterSt indicates that SFS affects “jitter” yet I haven’t seen an appropriate measurement that demonstrates this.

 

It is also maybe high time that you start reading the thread (I am serious, as you did not and think to allow yourself short cuts).

I spent 10 or so posts on this. Yes, including real life plots.

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1 hour ago, jabbr said:

One could for example provide a phase error plot at the carrier frequency of the bitstream.

 

I don't want to come across as mean (and most certainly not to you), but why don't you do that yourself ?

Fire up XXHighEnd, find the SFS setting (not hard), drag in your NOS1a/G3 DAC, hook up your measurement gear (I assume you have this running) and show us.

If you need to know where to put which probe in your NOS1, give me a call. :ph34r:

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1 hour ago, jabbr said:

I’m granting this — nonetheless for any given DAC, as isolation improves, effects such as input jitter become less apparent — by definition

 

Yes, your definition.

So your definition needs adjustment because it doesn't work out.

Stop the theories. First fire up XXHighEnd, drag in your NOS1a/G3 DAC, leave out the measurement gear this time and listen. Nothing could be more easy. All it requires is doing it.

 

You know, there's so much theorizing around in CA. Every body knows best. But this time you won't get away with it because it is too easy to test it yourself. Perfect show case. :rolleyes:

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38 minutes ago, acg said:

 For example, before galvanic isolation Peters NOS1 was immune to usb cables but then better voltage regulators became available and some additional regeneration and galvanic isolation had been added to the dac and it no longer is immune to USB cables and Peter even makes and sells a couple of variants.  Better isolation for sure,  lower noise floor,  a bit or so of extra resolution and better SQ but something that did not matter before now matters... and SFS changes if anything are more audible. 

 

Go figure!

 

And you know ... if I only had read this prior to my last sequence of posts. But I didn't. So Anthony (acg) not coincidentally tells exactly the same as I did. 100%. All he experienced is the same everybody did, if you only observe the behavior of your own gear.

And use XXHighEnd of course (which is not obligatory at all, but comes handy for the discussion here).

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@jabbr, So you have two inputs on your NOS1a/G3. The one is the USB isolated input (denoted "i") the other is without (but still has the internal i2s isolation) (denoted "u"). Try XXHighEnd and the SFS of our thread's subject and vary the input. Don't forget to use your Lush vs the stock cable (which is also good).

 

If you after this stil dare to participate with the same stipulations as you try to do so far, then ...

No, you won't. So no need to work this out further.

BUT

It would be very useful, regarding your knowledge by now on the phase error measurements. Again I am serious ...

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Phasure Mach III Audio PC with Linear PSU (manufacturer)

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17 minutes ago, PeterSt said:
4 hours ago, Audiophile Neuroscience said:

eg a regen or other isolating device, would, if the DAC were perfectly isolated, not make a difference in SQ.

 

 

just for the record, that's not my quote, but I confess it seems logical

 

22 minutes ago, PeterSt said:

 

The more galvanic isolation, the better the effects become audible. But someone just said it : the playback quality got better all over (say lower noise) and with the strength of the effect remaining the same, it thus becomes better audible. This is empirically found theory after the real life experience of the happening(s).

 

 

I am struggling with this. If not too much trouble can you further explain? If you get less noise coming through I am assuming will result in lower noise floor. Its the next bit that alludes me "with the strength of the effect remaining the same, it thus becomes better audible". If noise is the "effect", and it gets less....I am clearly not understanding, my apologies

Sound Minds Mind Sound

 

 

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3 minutes ago, Audiophile Neuroscience said:

just for the record, that's not my quote, but I confess it seems logical

 

F*ck, I had all prepared to edit it, but was one second to late eventually. So CA's quoting mechanism failed on me. Here's the correct quote/text :

 

6 hours ago, jabbr said:

A perfectly isolated DAC, according to my understanding of the term “isolated”, will have the same sound regardless of electrical differences in the “bit identical” incoming bitstream — eg a regen or other isolating device, would, if the DAC were perfectly isolated, not make a difference in SQ.

 

@jabbr, I am sure this makes sense to you, but not to me. It is high time that you describe your meaning of "isolated". Try to avoid the figurative speak now, because that doesn't help in understanding. It may also point you at not legitimate recursiveness (see, I can do it too O.o).

 

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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6 minutes ago, Audiophile Neuroscience said:

If noise is the "effect", and it gets less....I am clearly not understanding, my apologies

 

I suppose it is quite hard to seriously digest it when I say things in between all lines (seemingly), so again :

 

There is no noise as such regarding the matter of this subject (SFS changing the sound etc.). So the signal is not getting more noisy. But jitter in the digital domain is implied. And that in itself causes perturbations inside of the DAC (the receiver doesn't work evenly fluent and its not even current draw projects on the D/A section and now causes jitter there).

 

See ? another one in between the lines (braces !). Sorry for my style of writing.

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

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