When do measurements correlate with subjective impressions

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22 hours ago, 4est said:

In a recent post @plissken stated:

"Where certain measured characteristics track with your preferences, well I think knowing is better than not." in reference to measurements as they may pertain to someone's subjective preference."

Or perhaps by another poster @tmtomh:

"The only way to compile a large proportion of DACs that are significantly different (aside from power supplies, XLR vs RCA outputs, etc) is to look at analogue stages and in particular tubes (since ASR also has shown that op amp rolling doesn't produce significant differences), or to look at R2R DACs. ASR has reviewed some of both, especially the latter, and the measurements are there plain as day for those who are interested."

 

My question to you all is at what point would one consider something "true to the source" or indistinguishable in situ? Is there a an accepted number for THD, IMD or ?  that is considered close enough, or are we back into the 70 and 80s where we are chasing numbers down to zero? Realize this is a question about objective measurements seeking an objective outcome to subjective experiences.

All I can say is that I’ve tried a few of the ASR recommended DACs, including the Topping and they leave me flat. The measurements don’t correlate with great sound for me.

 

On the other hand @Miska posted some measurements here of certain DACs two of which I love including the Pro-ject  S2D (which benefits from a good power supply) and the IFi iMicro — which has terrific input isolation. 
 

I think the differences I hear — assuming a good basic product, are mostly to do with the output stages. 
 

For me, the measurements need to have a predictive value in terms of what I hear. 

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1 hour ago, Jud said:

 

Measured differences? In what measures? (Curious as to what if any measurable differences a cable might make as part of a system.) Are there any differences between cables that meet spec?

Sure there are differences. Different shielding is one example. The spec is a range. The rise times might be affected slightly. The cable couples the sending and receiving components - the D+\D- pair reduces differential mode noise but not common mode noise. Different shields can couple the components together and alter the common mode noise transmission. 
 

TL:DR - measure common mode noise transmission/EMI

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20 hours ago, Jud said:

there are things like the Aphex Aural Exciter, literally a piece of electronics to produce noise and hash,

The best kind:

 

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38 minutes ago, pkane2001 said:

 

That's where DISTORT can help. You can apply sub-Hertz modulation to a clock and see what sounds like. Apply it to a simple sine wave or to a full orchestra recording. You decide how much of each type of jitter to apply, from simple sine-wave, to random, to 1/f noise, to correlated and then listen, see if you can tell the effect.

You are really trying to get me to install Windows aren’t you?

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18 hours ago, CG said:

It just so happens that there's an interesting conversation posted over at Inner Fidelity.  It's not lengthy enough to be considered an interview, but it still is worth reading.  Or, so I think.  (As of right now, there are no comments...)  If you don't believe Audio Precision is objective enough for you, I don't know what to say.

 

https://www.innerfidelity.com/content/canjam-nyc-2020-audio-precision-measurements

I didn’t get much out of that article. The Audio Precision makes one type of measurement. There are many many others. High speed digital engineers use many tools. EMI testing labs are complex. Because a unit in one configuration using a single test setup displays a certain spectrum in the AP does not mean that the same unit will exhibit the same behavior in all situations — for example there are nonlinear effects such as IM, overload, common mode noise etc that are not measured unless specifically looked for.  

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21 hours ago, pkane2001 said:

 

I heard others had good luck using it with Wine on Linux and Mac.

Hmm loaded wine, got the app to show up on screen (Ubuntu 18.04 LTS) but can’t get it to easily show results... wine is a weird environment (as expected) ...

 

It would be cool to load a file containing a phase noise plot and run that against the music file.

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I’d like to see if @pkane2001’s distort software can simulate this. I would want to first upsample to 24/384, then apply a phase noise plot, then send to a low jitter DAC. That’s how I would do it on my system. 

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On 2/18/2020 at 11:35 PM, Jud said:

The one that I heard substantially before anyone else was slew rate limiting, and to me it was fingernails-on-chalkboard irritating, while from the reactions of others it seemed fairly innocuous to them.

Yes and from what @davide256 is saying about multiple instruments, I don’t think this is a digital only phenomenon. I’ve heard this at live concerts. I strongly suspect the amps are underpowered and get overloaded. 

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29 minutes ago, pkane2001 said:

 

So I installed Ubuntu 18.04 and put Wine 5 on it, then installed Distort. Seems to work OK, or did you also get this far with yours?

 

I got that far, then tried to load a music file.

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29 minutes ago, pkane2001 said:

 

So I installed Ubuntu 18.04 and put Wine 5 on it, then installed Distort. Seems to work OK, or did you also get this far with yours?

 

I got that far, then tried to load a music file.

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4 hours ago, Jud said:

 

They may not have to be pleasant. I remember a post you made a long time ago (you may not remember it or the events you recounted yourself, but perhaps you do) saying that in the PS Audio jitter tests at least some people liked more jitter. In a little test here of 3 pairs of files, both @bluesman and I picked the files with more jitter as sounding better. To me they sounded more "natural" and "dynamic." I make no representations that my own hearing and taste is any good, but @bluesmanis a professional musician with decades of experience who once on this forum accurately picked out the size of a grand piano from a recording. So what was it about the extra jitter in those files that made them sound more realistic to him, or was the result purely random?

 

So this is really a great question that gets at the heart of many issues!

 

1) could be random

2) could be something else

3) could be jitter

4) could be a particular interaction of the particular system and jitter

5) could be random ...

 

From a scientific point of view, rather than mere objectivism or subjectivism, you need to understand how to remove all these extraneous variables. You can listen but there are confounding variables, you can measure but there are confounding variables.

 

Sitting down and  measuring might be a similar hobby to simply listening, although the subjectivist wins here!!

 

🤷‍♂️

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Now, back to jitter ... who cares about jitter unless if affects YOUR dac? Why would we assume that all DACs are equally affected? They aren't. On the recording/ADC side, however, the ADC jitter will affect the recording, but there is no one single "jitter" that has universal audible effects. That said, it would be interesting to see what the lower audible limits of audibility of, say, close in phase noise vs correlated jitter -- the reason I separate the two are because:

 

1) correlated jitter is not primarily determined by the clock crystal, rather the circuit layout (crosstalk, ground bounce etc).

2) close-in phase noise is the only significant level of random jitter in circuits with reasonably good clocks.

 

The techniques for measuring close-in phase noise are well known but different from the other well known techniques for measuring correlated jitter -- it turns out that things like eye diagrams capture both so there ...

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10 hours ago, Allan F said:

To what extent do the conventional measurements generally performed on audio equipment really measure sound "quality", and are their additional measurements that can better inform us of it? By "quality", I do not mean in the common usage of how good it is, but rather the unique tonal characteristics of particular sounds, such as the timbre of musical instruments.

 

Good questions. 
 

On one hand, accurate reproduction of the sound should preserve the tonal characteristics of the sound. 
 

Forget neuroscience, at least for the moment: capture all the sound and accurately reproduce all the sound such that the vibrations transmitted to the ear are identical to those transmitted during the performance. 
 

No shortcuts.

 

10 hours ago, Allan F said:

 

In the same vein, how much do measurements using fixed tones correlate to the dynamic characteristics of the sound of music?

This is called linear analysis and has a good deal of correlation except that this type of decomposition doesn’t capture everything, for example Inter modulation distortions. 

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1 hour ago, PYP said:

 

What is the assumption about the role of the room in this measurement? 

Im describing an ideal music reproduction system. Room correction.

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16 minutes ago, Jud said:

If so, which should we strive for - that which sounds real, or that which is accurate?

We should get the choice!

 

Accuracy is more objective. What sounds “real” could be subject to the whims of someone else making a decision eg MP3

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17 hours ago, Jud said:

Here's something related I'm interested in, illusions. I wonder if there are audio equivalents to the visual demonstration below, where inaccurate amplitude (brightness) and frequency (color) *looks* accurate. Are there inaccuracies (besides sheer loudness) that sound closer to the "real thing" to us than accurate reproduction? If so, which should we strive for - that which sounds real, or that which is accurate?

Ever been to a concert with an electric guitarist who moves about the stage with microphone? If you sit close up, the sound appears to come directly from the mouth and guitar. Yet the guitar amp and mic amp remain in a fixed position on stage. Soundstage is truly an illusion!

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23 minutes ago, 4est said:

Thanks Jud! I haven't asked for moderation rights, but I will if necessary. I REALLY want this side of the forum to work. I hated the bickering, but I also hated losing some of those posters too.

Yeah you should moderate! No bickering but no vapidity either! You are the perfect blend of reasonableness and  technical sensibility ... we need on no BS filter with a sharp corner and linear falloff 😂

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1 hour ago, Jud said:

 

True, but unless you're watching a DVD or Blu-ray, the illusions at home must be purely audible. I'd still like to tie this to the very interesting question in the original post - whether any such illusions would correspond with particular distortion measurements.

oh man you got me there ... I’m going to stick to electronics and leave the psychacoustics for people smarter than me 😂

 

Seriously “perfect” replication of what’s recorded is a tangible goal ...

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9 hours ago, opus101 said:

The trouble with statements like that is that they're either meaningless or else self-contradictory when examined.

Occam’s Razor

 

Apropos to what we are doing is that things like Spice capture the components but not the parasitics. 3D SIV software is better but expensive and needs the actual board layout which is not available to third parties, 

 

Regarding “injecting” jitter into a file, this makes some big assumptions because jitter is a time phenomenon and files are not... in the same way that SPICE makes assumptions that board layout is not significant, the in accuracies of Meeks relate to assumptions. The other saying is “Don’t ASSUME ...” 😉

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1 hour ago, pkane2001 said:

 

A PCM file is voltage sampled over time... so it's not a time phenomenon?

 

Well it’s jitter that’s first baked and then frozen, so it might taste just like fresh jitter but might not, depending ...