Audio Science: Does it explain everything about how something sounds?

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Hello David

Another issue with blind tests is that one can easily be led to come up with a desired result very much like a magician pushing a card on to unsuspecting audience and making it look like it was all chance.

How??? So you think the person running the test has purposely set the test up to deceive the participants??? What is the point in doing that???

Rob:)
 
Perhaps you also ignore what I write! here us my question again: bolded for more directness! And I darn well know what a linear system is John.

Originally Posted by tomelex

Yes we don't know much about the ear brain interface, but pray tell me, as one who constantly belittles sine wave testing, if I pass any frequency, any amplitude, and any single or multiple sinewaves through a device, and I monitor amplitude, frequency and time on the output plus look at any distortions that arise, what is the missing test here then? Whats exactly not being picked up by such a test with sinewaves


Its simple, what is wrong with that test, what distortions does it not pick up of an everyday audio signal?

If you believe there is, then just say so and that you have no clue what it is, this extra dimension that the rest of the electronics world is un aware of and I will then never ask you again, promise.

What's wrong with that test is what I already stated - "it's limiting the potential excursions from linearity of this system"

I've been advocating multi-tone test signals with realistic crest factors for a while now as being more like music & more revealing of system issues.

I can cite Scott Wurcer (he of Analog Devices fame) admitting on DIYAudio that "The multitone really separates the sheep from the goats. I'm using 30 1/3 octave tones at about 12db crest factor. Artifacts show up on even the best boards."
And "As BV said a mutitone of sufficient length (and you can create any crest factor you want mathematically) will fully stress the system."

And although this isn't Wurcer speaking, it sums up nicely the thinking of what is wrong with simple test tones
The harmonics of a single tone produces some 'grass' on the FFT plot. Say .01% thd worth; Can't be heard. More simultanious tones, more grass growning and IM grass, too. After 20,000 tones have been applied, that .01% THD of each of thousands of tones adds up to enough to reach audible levels. The audible effect is an equivalent increase in the background noise level. Which is described as masking details or changing character of the sound depending on music freq content played. This might be why we need Really low thd numbers on a single tone test.... to prevent the accumulated harmonics of many simultaneous tones from reaching an audible threshold.

I already posted, in this thread, an anecdote from Jason Stoddard of Schitt fame
And…in terms of standard measurements, this DAC blew everything we’ve ever measured away. I mean, vanishingly low noise floor, virtually undetectable power supply harmonics, insanely low THD, flat frequency response…

…until you looked at the IMD, which gave numbers a bit higher than you’d expect, given the THD results. And the numbers weren’t related to the 1K spike…they appeared down low, below 100Hz.

What? We ran through our multitone test (it’s easy to do digital multitones on a Stanford as well, not sure about other analyzers) and the low-frequency numbers went bonkers. As in, there was a broad range of non-harmonically related distortion components from 10-90 Hz, at a fairly high level (-50dB or so). -50dB is potentially audible. And it was up nearly 90dB from the baseline measurement.
...............
So…while we putter around confidently with all of the accepted measurements, maybe there are still realms out there where “here be there monsters.”

That’s why we still listen. And measure. And come up with new measurements. And listen again.
 
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But like you, I don't believe "that there's always prejudice involved in sighted testing"
Exactly. That is belief. Wishful thinking (fallacy). Circular reasoning. The exact opposite of science and why we don't believe horses can count, people can bend spoons, etc, etc.
 
Hello David



How??? So you think the person running the test has purposely set the test up to deceive the participants??? What is the point in doing that???

Rob:)

Hi Rob,

There could be a variety of reasons, from self-promotion to commercial benefit and depending on setup the tests the outcome can be manipulated.

david
 
I've been advocating multi-tone test signals with realistic crest factors for a while now as being more like music & more revealing of system issues.
I can cite Scott Wurcer (he of Analog Devices fame) admitting on DIYAudio that "The multitone really separates the sheep from the goats.

:confused:
John, didn't you say on DIYAudio that (analog) measurements are useless:
I'm no expert in digital audio but one thing I can also see in these shots after having studied them a bit more is possible evidence of jitter reduction:
Again I will repeat, I doubt the analogue tests are capable of revealing anything worthwhile.
When did this change come about?
 
There could be a variety of reasons, from self-promotion to commercial benefit and depending on setup the tests the outcome can be manipulated.

david
Unlike sighted uncontrolled in-the-biz evaluations of course.
What about the blind tests free of those reasons?
Stuff done by Toole/Olive at NRC??
 
Forgive me, I see nothing in your posts that dispel that sinewave tests don't reveal stuff. Operating out of linearity is also revealed by sinewave tests. Multiple or not, you might read that is what I put in my question to you, so I guess you have no new theory, that's good, the electronic gods can rest peacefully tonight and so can I.

BTW, of course a sinewave multi tone measurement is not a new measurement, despite what schiitt says.

I know multitone testing is not new & if by "any single or multiple sinewaves through a device" you actually meant to say multitone signal (of many tones with suitable crest factors) then why didn't you just say that?

BTW, what do you consider is a reasonable number of such tones & what crest factor?
 
Unlike sighted uncontrolled in-the-biz evaluations of course.

You have to expand on this AJ and not sure what you mean by uncontrolled and what is acceptable control for you?

What about the blind tests free of those reasons?
Stuff done by Toole/Olive at NRC??

I never said that every single test is a sham, I'm sure there are plenty conducted for research purposes only. Specific to Toole/Olive tests the Dr. Toole's AES speech that Amir put up was an unadulterated marketing plug for Harman. Amir's behind the curtain shot of Olive and 3 revealed speakers was completely weighted in favor of their JBL 800 Array. What was the purpose of that blind test, convincing potential buyers or in house research? Let me clarify, I have respect for Dr. Toole and his work and I'm not denigrating him here, just pointing out that no one is above some good old fashioned self promotion.

david
 
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It is that truth I am trying to understand. The data we are discussing is a company making measurement equipment, saying this and that measurement is audible. Peter gave a thumbs up to that post. I am trying to figure out if Peter has now changed his mind and supports and believes in measurements reading on audibility of audio equipment. Because if he is, it is a turn around for him and we have accomplished something in this thread.

Amir, we certainly have a gross misunderstanding. I don't know if those particular measurements are audible. I enjoyed reading Al's post and learned something from its content. I remember reading something on the topic written by Nelson Pass on his Class A, Single Ended amps. I wrote that Al and Acks' posts were good because they stood in stark contrast to the content of some of the other posts at that time which I found to be very polarizing and argumentative and which I did not think added anything to the quality of the discussion.

I have always believed in measurements being able to explain something about the audibility of audio equipment. I just am not certain that Audio Science can explain EVERYTHING about how something sounds. That is my question and the reason I started this thread. At no time that I remember did I ever write that I do not find some validity to measurements. I have posted measurements of the frequency response of my system in my room. As an analogue guy, I rely on all sorts of measurements for the accuracy of my turntable set up. I relied on measurements to match my amps to my speakers, and then confirmed that by listening. I use a laser measuring device to precisely locate my speakers within 1/16th of an inch in distance, tilt and toe in from the listening seat.

I have no idea where you got the idea that I changed my mind about measurements. It leads me to wonder if you understand what I write in my posts. If not, then I need to be more clear, or you need to read my posts more closely. Please do not credit your contributions to this thread as having anything to do with me changing my mind about measurements. You would be mistaken.

I ask you again, what cause are you attributing to me?
 
Amir, we certainly have a gross misunderstanding. I don't know if those particular measurements are audible. I enjoyed reading Al's post and learned something from its content. I remember reading something on the topic written by Nelson Pass on his Class A, Single Ended amps. I wrote that Al and Acks' posts were good because they stood in stark contrast to the content of some of the other posts at that time which I found to be very polarizing and argumentative and which I did not think added anything to the quality of the discussion.
Let me summarize again: Question about audibility of THD was made by AJ. Al quoted some measurement company's web site on that. I am asking if your comment that this information was "great" is consistent with your position in this thread. What did you learn in that post that was great and related to the topic of this thread???

I have always believed in measurements being able to explain something about the audibility of audio equipment. I just am not certain that Audio Science can explain EVERYTHING about how something sounds.
You are not sure or you believe that it can't explain everything? What if it can explain majority of things? Or most? What then?

That is my question and the reason I started this thread. At no time that I remember did I ever write that I do not find some validity to measurements. I have posted measurements of the frequency response of my system in my room. As an analogue guy, I rely on all sorts of measurements for the accuracy of my turntable set up. I relied on measurements to match my amps to my speakers, and then confirmed that by listening. I use a laser measuring device to precisely locate my speakers within 1/16th of an inch in distance, tilt and toe in from the listening seat.

I have no idea where you got the idea that I changed my mind about measurements.
I didn't think we were including measuring a distance to a speaker in the context of the word "measurement." Or any other instrumentation you use for your analog gear alignment. There is certainly no debate about those topics among camps so let's not confuse the issue in a post where you are trying to clarify your position.

The debate is on value of audio science in its formal listening tests and measurements it uses to determine audibility of distortions and fidelity. It says that if you think your equipment sounds better after warming there better be some measurement that shows it. If you tell me that with no measurement difference you clearly can hear improvements, then you are completely at odds with measurements and audio science regarding it. Unlike what you post above.

It leads me to wonder if you understand what I write in my posts. If not, then I need to be more clear, or you need to read my posts more closely. Please do not credit your contributions to this thread as having anything to do with me changing my mind about measurements. You would be mistaken.

I ask you again, what cause are you attributing to me?
Your cause appears to be to cast doubt on validity of measurements to explain equipment fidelity. Don't see how you can do that in one breath and then turn around and give huge thumbs up to a post that copied the statements of a company making measurements and assigning audibility to it.
 
I have always believed in measurements being able to explain something about the audibility of audio equipment. I just am not certain that Audio Science can explain EVERYTHING about how something sounds. That is my question and the reason I started this thread. At no time that I remember did I ever write that I do not find some validity to measurements. I have posted measurements of the frequency response of my system in my room. As an analogue guy, I rely on all sorts of measurements for the accuracy of my turntable set up. I relied on measurements to match my amps to my speakers, and then confirmed that by listening.
I use a laser measuring device to precisely locate my speakers within 1/16th of an inch in distance, tilt and toe in from the listening seat.

I like that...the level of precision and dedication. ...Like many other WBF members. ...Me included, up to a certain level...my own measuring level...humble. :b
 
You have to expand on this AJ and not sure what you mean by uncontrolled and what is acceptable control for you?



I never said that every single test is a sham, I'm sure there are plenty conducted for research purposes only. Specific to Toole/Olive tests the Dr. Toole's AES speech that Amir put up was an unadulterated marketing plug for Harman. Amir's behind the curtain shot of Olive and 3 revealed speakers was completely weighted in favor of their JBL 800 Array. What was the purpose of that blind test, convincing potential buyers or in house research? Let me clarify, I have respect for Dr. Toole and his work and I'm denigrating him here, just pointing out that no one is above some good old fashioned self promotion.

david

Show me a single example of Harman promoting the results of their research and this implication will have merit. But you won't find one. Their research is for product development; they have deliberately not published their product's rankings relative to their competitors included in their studies.

Tim
 
Show me a single example of Harman promoting the results of their research and this implication will have merit. But you won't find one. Their research is for product development; they have deliberately not published their product's rankings relative to their competitors included in their studies.

Tim
I think you saw the same AES video where Dr. Toole spends the entire time talking about Harman, Harman test procedures and concludes the speech declaring the M2 as the best speaker around. If that's not self promotion then what is? He was also quite obvious when he was knocking the ML speaker in the test.
david
(Edit) To avoid any misinterpretation and for the record, what I wrote above isn't a criticism of anyone and I owned many JBL speakers over the past 20 years.
 
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... I use a laser measuring device to precisely locate my speakers within 1/16th of an inch in distance, tilt and toe in from the listening seat. ...

I trust your listening seat includes a dentist-style headrest to locate your ears to the required accuracy.
 
years ago I built a device which can create 20 test tones, and the crest factor is viewed on the scope to make sure the DUT bandwidth can handle it. I have my own way of doing muti tone tests, like most audio guys do and they don't share and neither do I. I also have other stuff using fft etc but I like my old rig the best. Lets just say that null testing is a big part of it (my rig).

Somehow I find it hard to reconcile this post & your coyness about "your measurements" with your previous reply along these lines!!

Atmasphere said:
Can't and don't are pretty different. Right now the tools don't seem to exist for the measurements I'd like to make... and that would be what sort of distortions show up when the waveform is in constant change (such as a musical signal) as opposed to a sine or square wave. As far as I know that technology does not exist. Yet that would tell us a lot more than we get right now!
are we not designing for linear circuits anymore?, but agree this device would be very useful.

What I don't see in this exchange or later is any mention or awareness of multitone tests & how they almost fulfil this requested measurement by Atmasphere. You certainly don't recognise, in your rely to him, the fact that multitone tests are exercising the non-linearities of the playback electronics!

So, forgive me if I remain unconvinced by your latest claims & coyness about the details. Any small detail you do give are incorrect - crest factor has nothing to do with bandwidth. I sense that you don't really know much about a true multitone test for one who says he used/uses it.

If however you are playing forum debating tactics by being clever with your composing a sentence that is open to interpretation "if I pass any frequency, any amplitude, and any single or multiple sinewaves through a device, and I monitor amplitude, frequency and time on the output plus look at any distortions that arise, what is the missing test here then? Whats exactly not being picked up by such a test with sinewaves" then count me out of your little game - I'm not playing

I also asked you a while ago what null level you think defines "no difference" but you avoided answering. Perhaps you want to tell us now after raising the issue again?
 
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I think you saw the same AES video where Dr. Toole spends the entire time talking about Harman, Harman test procedures and concludes the speech declaring the M2 as the best speaker around. If that's not self promotion then what is? He was also quite obvious when he was knocking the ML speaker in the test.
david
(Edit) To avoid any misinterpretation and for the record, what I wrote above isn't a criticism of anyone and I owned many JBL speakers over the past 20 years.

I spent my career in marketing. A speech at an AES meeting is not marketing. An ad that mentions the test results and compares them to the performance of competing products? A mention on their consumer web site? In a brochure? A release to the audio press? A speaking tour to audiences of audio dealers? That's marketing, growing less effective and to a smaller target audience at every step. A presentation to peers at a professional association meeting? No. Not even close. And that's not semantics or a matter of an opinion. No marketing professional would call that marketing.

Tim
 
......

The debate is on value of audio science in its formal listening tests and measurements it uses to determine audibility of distortions and fidelity. It says that if you think your equipment sounds better after warming there better be some measurement that shows it. If you tell me that with no measurement difference you clearly can hear improvements, then you are completely at odds with measurements and audio science regarding it. Unlike what you post above.


Your cause appears to be to cast doubt on validity of measurements to explain equipment fidelity. Don't see how you can do that in one breath and then turn around and give huge thumbs up to a post that copied the statements of a company making measurements and assigning audibility to it.
Amir,
this seems a bit lopsided :)
Measurements do show that amp behaviour can change in the first 1-2 hours, if going by just THD then the changes are small but it shows a behaviour change is occurring electronically/thermal operation window.
However it is fair to say then that while these are very small measurements it shows something is happening, therefore it makes sense to investigate further, with different measurements and with scientific listening tests, however as I said earlier and has been ignored by several if one does not have a scientific study (which this does not) then the only option is to fall back to engineering and the top experienced-knowledgeable engineers.
There are objectivists jumping the gun saying it is not actually happening and it is cognitive bias/confounding/etc because there are no scientific studies done, but they ignore the engineering community and measurement behaviour of quite a few amps; their response is THD is miniscule and so the amp behaviour is meaningless while ignoring electronically there is a change and that maybe further engineering investigation is required (that can bring us to notable engineers such as Nelson Pass and others who point out some amplifiers including SS do change between cold start and warmed-up)....

Now when you passed the final (where a lot of the issues were resolved such as db difference otherwise the test would had been voided) hirez vs cd quality ABX what were the measurements in regards to what was different and at what level were these variables?
I bet they were at a meaningless low value :)
If that is so, well one cannot ignore the measurements and correlation (at some point it should be modelled) with your test, but that is what a lot of that passing the ABX was about; it focused specifically on only one aspect of scientific study and that was a listening test, all the other aspects (measurement-correlation-modelling) are just as critical including the question I just asked.
Anyway looking forward to knowing more about the measurements and values with regards to your hirez vs CD abx pass.

Edit:
OK the above is bold because my point is already being taken out of context and my post completely skewed...
Sorry Groucho but you are taking it in the wrong direction, which is a bit annoying as it is misdirecting from what I was asking and mentioning.
Thanks
Orb
 
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