Misleading Measurements

[fas42]

37 minutes ago, pkane2001 said:

 

I usually measure a component with a 60Hz (regular US mains frequency) and at 70Hz. If there’s any mains dependency in the component, it will show up as a frequency difference in the spurious tones in an FFT, or a change in the noise floor.

 

Which is not measuring what I'm talking about - one way, out of many possible, of determining what I consider important is to inject a sweep of frequencies, starting from the mains frequency, to the mains plug of the component while it is powered up, and monitoring what happens to the noise spectrum.

[fas42]

28 minutes ago, pkane2001 said:

It’s easier to just compare a component plugged into a wall outlet to one plugged into a power regenerator that has none of the junk. 

 

And who has posted details of what they've found?

[fas42]

6 minutes ago, pkane2001 said:

I have, and I’ve seen Amir post comparisons with a laboratory power supply with regeneration vs. just a wall outlet.
 

When testing one of the audiophile power supplies, I recommended to him  to use the 70Hz trick and he confirmed that the supply was leaking that frequency from its own power line.

 

Any links?

[fas42]

First thing I found was a post by Amir, where he said,

 

Quote

I actually have one of the old PS Audio regenerators. I measured it once and it is as clean as my Lab AC generator. So it does what it says but again, won't make a difference in the analog output of the audio product.

 

So, he has the assurance of knowing how all audio components behave, without even measuring ... 😉.

[fas42]

Okay, bit of detective work later, he's using a BK Precision 9801 AC generator - hmmm, I would be much happier if it were a 9833 model - 3,000VA versus 300 for the 9801. ... But, a decent start, 🙂.

[fas42]

And, the very thing that would be useful, which would to introduce higher harmonics, to make things interesting, is missing... looking around, one company that's producing meaty products getting much closer to being fully versatile is Chroma, http://www.chromaate.com/product/Regenerative_Grid_Simulator_61809_61812_61815.htm

 

[fas42]

Another interesting bundle of thoughts I just came across, when someone asked for some noise making ideas ... https://www.eevblog.com/forum/projects/intentionally-injecting-noise-into-supply-rails/

 

 

[fas42]

32 minutes ago, pkane2001 said:

 

As if he was reading this, Amir just posted measurements of an AudioQuest powerstrip, measuring its advertised line noise filtration capabilities. Apparently it does filter above 30kHz, but leaves all of the junk in the audio band. Who knows, it may actually be useful for some audio devices that don't have good filtration at the power supply.

 

IME, all audio devices don't have good filtration at the power supply - that is, it's trivially easy to introduce some electrical noise making device or process into the environment, and hear the impact on the SQ ... just read the reports of companies struggling to get good sound in a show situation, and how they had to deal with the "lousy hotel power!"

[fas42]

27 minutes ago, Jud said:

A few years ago I conducted a little test here in the forums. One acoustic guitar (classic Gibson, big round sound hole) was playing in one channel, a very different acoustic guitar (a very old Epiphone with small f-holes like a violin) in the other. The task was to determine which guitar was playing in which channel. Self-declared objectivists were given a selection that repeated 2 seconds on and 2 seconds off for 30 seconds. A rapid comparison, as an objectivist can tell you, is best for discrimination when doing the most common form of blind testing, i.e., listening to selection A, then quickly comparing it to selection B. So that's why they got that sort of test, even though there was no sequential comparison - both guitars were playing throughout the 2 seconds, one in each channel. Self-declared subjectivists were simply given a 30-second selection, because they don't tend to be concerned about quick comparisons, the length of echoic memory, and suchlike.

 

 

Sorry, I think this type of testing is complete nonsense - of zero value, in every possible way. Yesterday, I got a result - a negative one, in fact - which to me is of vastly greater value: I played a track of a live blues performance, quite recently recorded - I have played this track close to a 100 times; and I know exactly what the sense of it can be ... it was a fail on the new digital speakers of mine - nothing was missing, all the bits were there; but the vitality, the sense of the occasion was poorly rendered - it was, boring ...

 

Okay, I could explain why that was so - the system hadn't warmed up enough, there was too much interference from somewhere, there was some issue that I still haven't unearthed, etc - but that's not the point; what I instantly knew at that moment was that I had a handle, in terms of some piece of music, that would tell whether the rig was firing at an acceptable level.

[fas42]

8 hours ago, manisandher said:

 

In the ABX, I was primarily picking up an ever-so-slight edginess in the piano in one and not in the other sample (both bit-identical to each other).

 

 

Yes, one uses "tells" in the reproduction - the "ever-so-slight edginess" is the giveaway of audible playback chain distortion - and certain tracks will send levels of this through the roof; making what's going on obvious.

 

No, this is not the recording ... I'll repeat 😝, "this is not the recording" ... careful optimisation of a system makes all the "ever-so-slight edginess", in all the recordings, vanish - this is the process of audio conjuring, 😉.

 

[fas42]

1 hour ago, pkane2001 said:

 

Yet another explanation, is of course, that with distortions below a threshold of audibility, the devices all sound the same.

 

That's how it works, in fact ... all devices will subjectively sound the same, once all significant distortions are below a threshold of audbility - this in fact makes it easy to pick up flawed playback, because a particular recording or track will be twisted into a peculiar variant of what one knows actually exists on the recording - an accurate analogy is applying a Photoshop filter to an image, to give it an "artistic look" - fun to do, but irrelevant if one wants to know precisely how the original presents.

[fas42]

1 hour ago, The Computer Audiophile said:

Did they “fix” stuff in the audible range or just make it look better for those who like measurements?

 

Serious question. 
 

I know they fixed the zero crossing glitch just to appease people who looked at the measurements. 

 

To make it look better ... as someone who barely worries about the technical perfection of the components I come across, but instead focuses on eliminating subjective "glitching " in the SQ, I can understand why they did this - they would be amused at the jumping up and down of those who obsess about getting good numbers; but appreciate that they increase their audience, by appeasing them ...

[fas42]

On 7/8/2020 at 9:10 AM, fas42 said:

 

Sorry, I think this type of testing is complete nonsense - of zero value, in every possible way. Yesterday, I got a result - a negative one, in fact - which to me is of vastly greater value: I played a track of a live blues performance, quite recently recorded - I have played this track close to a 100 times; and I know exactly what the sense of it can be ... it was a fail on the new digital speakers of mine - nothing was missing, all the bits were there; but the vitality, the sense of the occasion was poorly rendered - it was, boring ...

 

Okay, I could explain why that was so - the system hadn't warmed up enough, there was too much interference from somewhere, there was some issue that I still haven't unearthed, etc - but that's not the point; what I instantly knew at that moment was that I had a handle, in terms of some piece of music, that would tell whether the rig was firing at an acceptable level.

 

As a follow up, this was largely resolved by altering how some computer gear at the other end of the house, on a different circuit, was plugged in - another example of why it's so important to resolve mains quality issues ... a kludge solution - some capacitive filtering across the socket was simply done another way; which happened to suit the particular assembly of devices plugged in ... of course, the long term method is to improve the specific filtering done for the rig components - so, need to buy some more electronic bits, to experiment with, 😉.

 

What was gained? ... The sense of liveness to the music making was lifted substantially - the fire was back ... now, how does one measure what's happening here - with numbers?

[fas42]

13 hours ago, Jud said:

 

For vision, the brain is extremely specialized, down to some groups of neurons recognizing horizontal features, others vertical. I’m speculating that recognizing when a familiar piano sounds just a very little bit “off” may be handled differently in the brain than trying to recall whether a musical passage you heard 20 seconds ago sounds different than one you’re listening to now. (Note “trying to recall” in the second half of the sentence but not the first.)

 

 

Just now thinking about how I register how a setup is misbehaving, I see how the pattern matching mechanism of the brain can operate - for some, 😉. Put on a track I'm familiar with, "it sounds different" - why is it different? Without consciously thinking about it, my mind is picking up the pattern of how the anomalies are manifesting, it 'sees' the rhythm in what's going on - put on a completely different recording; the brain starts looking for that same rhythm to be there, and, yes! There it is - the glorious 'signature' of the rig, at that moment, is now very audible, it's quite obvious; and will become more and more annoying, because it overlays, everything ...

[fas42]

8 hours ago, Ajax said:

 

My experience has been that you will never convince any of these guys that they need measurements because they have the potential to undermine "their" hobby. Who wants to be told that they just spent a heap of doe on a piece of gear that doesn't do anything. Who wants to look like a fool?

 

 

I wonder why people on that side of the fence always miss out on adding a certain phrase here, as in, "My experience has been that you will never convince any of these guys that they need (all the subjectively relevant) measurements".

 

Guess it's 'cause they don't understand what the concept of https://en.wikipedia.org/wiki/Necessity_and_sufficiency really means ... 😉

[fas42]

1 hour ago, Audiophile Neuroscience said:

 

Compounding all of this are various other factors including performance anxiety etc. The "trying to do it - focus" thing I previously mentioned,  not only includes looking at such interferences as muddled memory issues hampering your efforts but specifically also the interfering effect of the act of trying itself. It could maybe related or likened to Hawthorne observational bias / observer effect in physics? Certain perceptual and even motor performance tasks are simply defeated by the act of focusing on the task itself, especially if forced or 'on demand'. It appears to interfere with unconscious infratentorial (beneath hemispheres) 'automated' and patterned reactions or sequences and also shutdown necessary supratentorial cerebral associative connections necessary for many perceptions.

 

Talking of methods of reducing "performance anxiety", what I do just prior to listening to new, unknown setup is presume that it will be so fantastic, shake all my earlier beliefs as to how good a system can be - and listen with that mindset. IOW, what I'm listening to has "to convince me" that it is indeed imperfect - which it generally always does, 😁.

[fas42]

 

7 hours ago, manisandher said:

 

But it didn't sound anywhere near as good to my ears - washed out and flat in comparison to the Phasure. So it went back to the dealer for a full refund. (I still changed the Phasure though... but for one of my old turntables. It's been fun exploring my record collection again... though I'd never go back to vinyl permanently.)

 

Mani.

 

Yes, this is the one of those "highly relevant but ignored, because we don't how to measure it" distortion behaviours - to compensate, just measure everything where it's easy to do so twice as much ... surely in the end all that vigorous probing will deliver a superlative result, just from all the energy put into the number readin', 😉.

[fas42]

The agenda of those with an objectivist stance is that measurements always win. Over people. If there is a dispute whether the measurements are right, or people's hearing is right - those on the other side will always give the thumbs up to the numbers; because, people can't be trusted, 😜.

 

Their determination is so strong that this is "how things work!" ... which means that they do whatever is needed to undermine the 'subjectivists' - ridicule, humour, contempt, anger, patronising tone, scorn ... whatever it takes - all that matters is that their stance is never threatened to any degree, by the possibility that they may be even a tiny bit wrong ... 😉

[fas42]

40 minutes ago, The Computer Audiophile said:

I don’t see it that way and that isn’t the crux of this thread. If measurements always win, this thread wouldn’t exist because objectivists would accept all products which measure better, not just those in certain categories.  

 

The objectivists will believe that the product with the best measurements in a category is the best. Full stop. Then they will decide if the cost of the item is reasonable, for them to consider for purchase. Excellent value for money, with all the measurements of an acceptable standard, will most likely be the winner, for their own systems. IOW, measurements beyond audible value will establish a ranking, on a selection list - something for them to aspire to; if they had the dosh to splash around, 🙂.

[fas42]

58 minutes ago, pkane2001 said:

The point is that there can be no generalized correlation if individual’s preferences are involved. There will always be someone who will prefer something different.

 

It's the "prefer something different" that gets some people not strongly in the objectivist camp riled up - the refusal to accept that people's hearing can actually determine whether one version of a playback is more accurate to the recording content, than another.

[fas42]

8 minutes ago, The Computer Audiophile said:

 

I just don’t like hypocrisy. 

 

In the OP, you said,

 

Quote

I would love to know why objective people are interested in anything below the threshold of human hearing and why they are interested in this info given that it can cause the same issues they rail against with respect to subjective opinions

 

That post of mine was a direct answer to that - the hypocrisy angle is not relevant to that. . 

[fas42]

Just now, pkane2001 said:

 

Soundstage is perfectly defined by phase and level differences between the left and the right channel, plus reverb. In fact, most soundstage in recordings is artificially created using these tools in mastering, so we know exactly how it’s produced and therefore how to measure it.

 

Incorrect. At a simplistic level, yes, true - but a high performing system reproduces very low level detail far more clearly, allowing the ear/brain to decode the meaning of this extra, usable information - anyone who has had a rig evolve into a state of tune allowing this fuller appreciation of the soundstage capture has an understanding of what is possible; and at least has an intuitive idea about how to move his setup towards this capability.

[fas42]

1 hour ago, pkane2001 said:

I’ll ask you the same question: do you have any objective evidence for this claim aside from your personal experience 30 years ago?
 

Because I can certainly cite books and studies that support mine, having been looking into spatial hearing and how to reproduce realistic 3D sound for the past few years.

 

And I would say, of course the research is not out there - the problem is similar to that of the intent of LIGO; if you want to detect gravity waves the sensitivity, precision of the measuring devices have to be at least to a certain standard - all papers I've seen, in audio, make assumptions about how good the systems have to be to get significant results - and it's clear, to me, what they use are way under what's needed.

[fas42]

26 minutes ago, pkane2001 said:

 

 

Here you go:

 

 

As I said, in most recordings soundstage is artificially generated, instruments and voices placed at desired positions using level, phase, and reverb. The soundstage you hear is defined by those parameters. Perfectly.

 

 

Gosh, those recording guys back in the 30's were clever! They managed to create a depth layering of the players using level, phase and reverb - amazing what they cooked up with the simple valve technology of the day  ...

 

And all along i though it was that it was a simple single microphone, with the instruments arranged in distance from the microphone so that a good overall balance was achieved  ... silly me!

[fas42]

5 minutes ago, Audiophile Neuroscience said:

I agree and including speaker type and placement and the room interaction. That said I do hear soundstage differences in DACS. IME high end MSB DAC in particular throw out enormous soundstage...and as Paul even said said:"Measuring how a DAC affects a recording is exactly what measurements do, including if soundstage will be affected."

 

Quick quiz ... is the MSB DAC magically distorting what's on the recording to create an artificial, "enormous soundstage" - or is that expansive space just sitting and waiting, in the digits of the source data, to be brought out alive into the world? 😉