How can DAC's have a SOUND SIGNATURE if they measure as transparent?

[antcollinet]

Thanks for the responses so far.

To address a few points :

I know reviewers may be biased, may have different imaginations, pre-conceptions etc. not that they are necessarily out to con anybody - many of these reviews are superbly done, for what they are, and I’m grateful for them. Food for thought makes life interesting!

I know I could just ‘enjoy the music’, which I do, but this forum is about understanding why, isnt’t it? Even if the answer is that there is no ‘why’ in this case.

I’m an engineer but not an audio scientist. So I’d love to be educated by audio scientists, as to whether there is a measurable or scientific reason why one DAC may sound different to the other if they are equally resolving.

More comments welcome.

As an engineer - what do you mean by equally resolving?

 

[Enstip]

Ooh now I feel like I’m being examined….

What I mean is, both devices can extract the same amount of detail from the digital stream and convert it to analogue with the same level of accuracy (linearity, distortion etc).

I guess also, I’m assuming that output stages can achieve the same performance.

 

[SIY]

Ooh now I feel like I’m being examined….

What I mean is, both devices can extract the same amount of detail from the digital stream and convert it to analogue with the same level of accuracy (linearity, distortion etc).

I guess also, I’m assuming that output stages can achieve the same performance.

Just to be clear, there is no “detail” in a digital stream, just numbers.

 

[solderdude]

There is nothing to 'extract' from a digital stream though.
It is received, processed (upsampled and reconstruction filtered) and converted to two analog output voltages.
There can be small inaccuracies in the conversion process and some extra distortion may be added by the analog output stage.
In both cases the 'changes' compared to the analog bandwidth limited and sampled waveform can be extremely small and beyond any audible levels even when using cheap components.

 

[Mart68]

Ooh now I feel like I’m being examined….

What I mean is, both devices can extract the same amount of detail from the digital stream and convert it to analogue with the same level of accuracy (linearity, distortion etc).

I guess also, I’m assuming that output stages can achieve the same performance.

all DACs measured here are measured from the analogue output so the performance of that stage is included in the measurements.

There's varying levels of noise, distortions, linearity etc but it's tough to find one where one or more of those aspects is bad enough that it is - or may be - audible.

So arguably you can say the vast majority are equally 'resolving' - for practical purposes i.e using them to listen to music.

 

[fpitas]

Just to be clear, there is no “detail” in a digital stream, just numbers.

Nothing past the decimal point?

/

 

[Koeitje]

I’m an engineer but not an audio scientist. So I’d love to be educated by audio scientists, as to whether there is a measurable or scientific reason why one DAC may sound different to the other if they are equally resolving.

You should also be interested is psychology. Psychology is just as important as the engineering and measurements.

 

[antcollinet]

Ooh now I feel like I’m being examined….

What I mean is, both devices can extract the same amount of detail from the digital stream and convert it to analogue with the same level of accuracy (linearity, distortion etc).

I guess also, I’m assuming that output stages can achieve the same performance.

So - there are three options.

Both devices are equally accurate, and the level of inaccuracy of each is below the level of audibility. Both will sound the same.
Both devices are equally accurate and the inaccuracy is audible - but both exhibit identical flaws. Both will sound the same.
Both are equally accurate, the inaccuracies are audible AND different. They may sound different.

This thread is specifically about the first case. Both devices measuring as transparent. In this case there can be no audible difference between them. If they are outputting equally accurate signals and the flaws are below the level of audibility, then that MUST be the case, right?

 

[Geert]

Just to be clear, there is no “detail” in a digital stream, just numbers.

Spoiler

There's a spoiler function for such statements ;-)

 

[Enstip]

There is nothing to 'extract' from a digital stream though.
It is received, processed (upsampled and reconstruction filtered) and converted to two analog output voltages.
There can be small inaccuracies in the conversion process and some extra distortion may be added by the analog output stage.
In both cases the 'changes' compared to the analog bandwidth limited and sampled waveform can be extremely small and beyond any audible levels even when using cheap components.

I guess I was applying the term ‘extract’ to the whole process of turning digital to an analogue line signal.

 

[jhwalker]

So - there are three options.

Both devices are equally accurate, and the level of inaccuracy of each is below the level of audibility. Both will sound the same.
Both devices are equally accurate and the inaccuracy is audible - but both exhibit identical flaws. Both will sound the same.
Both are equally accurate, the inaccuracies are audible AND different. They may sound different.

This thread is specifically about the first case. Both devices measuring as transparent. In this case there can be no audible difference between them. If they are outputting equally accurate signals and the flaws are below the level of audibility, then that MUST be the case, right?

Well, sure, if you define it that way. You START by claiming "both will sound the same". So both MUST sound the same. That's starting with a conclusion.

If you do not accept the first statement is correct (e.g., even if the level of inaccuracy is SUPPOSEDLY below the level of audibility, it may not actually be; i.e., there may be other factors we are unaware of that influence our perception of such sounds), then the second does not follow.

I'm not stating I do or do not believe any such thing, but you can't start out by making a flat, unproven statement and then using that statement to drive your conclusion.

 

[ahofer]

What I think he is getting at is that he doesn’t buy that the threshold of audibility *as defined here at ASR and in the scientific literature* is the actual threshold of audibility.

Otherwise this is all circular and can be reduced to the question-begging statement: We can’t hear things below the threshold of audibility.

 

[Wanman]

So arguably you can say the vast majority are equally 'resolving'...

You could. You could also argue they sound different from one another. For one thing amateur blind testing should not be taken seriously. Human perceptual testing is its own area of expertise. It takes more than just common sense to do it well.

 

[ahofer]

Human perceptual testing is its own area of expertise. It takes more than just common sense to do it well.

If more people appreciated *why* that is the case, this forum would be less repetitive.

 

[Blumlein 88]

This business about soundstage differences comes down to what data do you have to work with. In the recent series of posts, we start with an uncontrolled sighted evaluation. Pretty suspect right there. Plus we don't know what the other DACs were. Is there any similarly priced DAC that sounds different than an RME? Well what is the other DAC(s)?

After that everyone is by necessity making assumptions. You'll never come to a conclusion this way. It is a big circle-jerk. Of what we know that was described, uncontrolled review evaluations are nearly always meaningless. Did levels even get matched? After that tell us more or there really is not anything worth saying.

 

[ahofer]

It is a big circle-jerk

Without a climax.

I’ll show myself out.

 

[Wanman]

If more people appreciated *why* that is the case, this forum would be less repetitive.

Some suggested reading material to start with:

Also of possibly related interest: https://www.frontiersin.org/articles/10.3389/fnins.2016.00524/full

 

[notsodeadlizard]

Formulate the question differently, and the answer will be much easier to find:

Let us assume that one of the components (units) of the set of sound reproducing equipment is characterized by a large set of parameters some of which are artifacts below the listener's sensitivity threshold.
Under what conditions and in what combinations of components (units) of sound reproducing equipment can these artifacts become audible?
What specific parameters of components (units) can lead to the displacement of the additional spectral components (because of non-linearity and non-ideal nature of real devices) in the audible (perceived) area?

This question (this is one difficult question) is completely natural because the formal measurements of the parameters of a some component (unit) and its actual operation in a system of non-ideal units are completely different things.

This is so obvious and simple.

 

[antcollinet]

Well, sure, if you define it that way. You START by claiming "both will sound the same". So both MUST sound the same. That's starting with a conclusion.

If you do not accept the first statement is correct (e.g., even if the level of inaccuracy is SUPPOSEDLY below the level of audibility, it may not actually be; i.e., there may be other factors we are unaware of that influence our perception of such sounds), then the second does not follow.

I'm not stating I do or do not believe any such thing, but you can't start out by making a flat, unproven statement and then using that statement to drive your conclusion.

I was replying to the statement above mine.

 

[Wanman]

What specific parameters of components (units) can lead to the displacement of the additional spectral components (because of non-linearity and non-ideal nature of real devices) in the audible (perceived) area?

Its not just spectral components, Relative phases of test tones may also be audible. Example files of phase shifts that are audible: https://purifi-audio.com/blog/tech-notes-1/doppler-distortion-vs-imd-7#blog_content

"...The problem is, you can’t easily see from a spectral plot which of the two is actually the case. In fact, you can’t see it at all. That is because spectral plots don’t show phase information."

Besides auditory perception is much more complex than simple spectral analysis. https://en.wikipedia.org/wiki/Auditory_scene_analysis