The current state of psychoacoustics

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frugal-phile™
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mrfeedback said:
Dave, I'm tripping and you're stoned, supposedly, according to Bill.

He probably just assumed that since BCers grow the best pot in the world, we all must be stoned (it is probably only 35% and those people aren't stoned all the time)


My interpretation of that is that you really do not completely understand the subject of audio

I don't think anyone, anywhere, anytime completely understands the subject of audio.

The sensations produced by sounds ? - does this mean the emotions induced tempo, key, intonation etc as is used so extensively to portray moods in movie soundtracks ?.
Or the emotions induced by distortion mechanisms, be they noise, THD, IMD, frequency response abberations, jitter etc ?.

The emotional response of both of these mechanisms can vary considerably amongst human bio-units, depending on heredity, training, experience, and life.

In the end the only measure that counts is whether that person can enjoy the music. Certainly analytic tools, experience, and art can play a big role in making that possible.

I do not believe that fine differences between equipments cannot be measured, rather that the appropriate tests are not being performed.

I too believe that they can be measured, but also that what to measure and how to measure it are still quite immature -- perhaps akin to the blood-letting stage of medicine -- on 2nd thot probably not quite that far back.

dave
 
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CHRIS8 said:
Due to lack of controls, I have to doubt the validity of these results. Their are various tube amplifiers with distinct responses, dependant on the net reactance of the impedance of the speakers with the output impedance of the amplifiers.

I got the impression that the tube kit was PP (something like ARC perhaps) so the impedance driven tonal balance that SE amps can have probably didn't play a role.

I am also left with the impression that quite a bit of care was taken in the experimental design -- it was a while ago that i read it.

Also, maybe the AUDIBLE differnces caused by a tube vs ss were the objective?

One of the things that struck me about the study was that they were not interested in trying to assess the audible differences, only the subconsious results (measurement of the relative state of relaxation before & after a session) that struck me as very interesting.

....gimme gimme link!

I have my own curiousity arroused now too. The URL is no doubt bookmarked, but finding it in the thousands of poorly organized URLs i have will be a task (and i am somewhat time pressed at the moment). I am noodling over a strategy, and remembering clues, that will help me find it, even when i am doing other stuff... stay tuned.

dave
 
Hi Bill,
" I never said I believe that absoulte polarity was inaudible. I said that I could probably find a reference that said that. Later I stated that I didn't know because I never tried it but that I may do so even though I might be skeptical."

Ahhh, some honesty is coming out - if you have not tried to discern the audibility of AP, why make reference to such an article at all ?.
And why might you be skeptical ? Because of previously read or heard information (misinformation) ?
The key here is to approach with a fully open mind, and open ears, and do the experiments carefully and repeatedly, and then arrive at a conclusion, that is valid for the current experimental conditions.

The first step is to detect a difference in sound (or induced feeling/mood), and if so, which you prefer.
It is very natural to interpret just about any fine change initially as being a positive change, and this reflex reaction needs to be suppressed, and instead listen for fine details in the nature of the change.

This can take extensive A/B comparison, as you educate your ears/brain/mind system to null the similarities in the test examples, and instead home in on fine differences in the way particular voices and instruments are portrayed, and how these different sounds affect down into your soul.

"No matter where you are, you've just arrived and are in the process of leaving."
Doesn't that mean you never know where you're at ?.


Hi Dave, Yes I agree perfectly with all that you so succinctly say, except that I once had a BC friend who reliably informed me that Oz grows the best, in his opinion. :)


Hi CHRIS8,
"The tests I have seen performed resulted in 50/50."
You need to do your own rigourous testing.

"This is an error type that is heavily discussed by Levanthol in his AES papers. The problem: cost."
So I am not the only one saying this ?. Cost - further supports my assertion that usual blind testing is inadequate.

"An unsubstantiatable claim. I have heard it 1001 times before"
It is perfectly substantiable because it is perfectly true.
Like I said earlier, it takes a very good system, familiar music, a quiet home environment, and lots of and repetitious A/B testing to train your ears/brain to be discerning.
You have a very fast FFT between your ears if you teach yourself how to use it.
With practice and learning , you will be able to do this yourself at home reliably.

"The feeling/sensations produced BY sounds. Meaning, variable effects on the senses, from a control sound source. This could, for example, mean the study of effects of a controlled level of distortions in a signal, to observe the effects on various people. Bascily, any controlled sound, and the resultant effect on the test subject"

The Anthony New article assserts
"as far as I can see, harmonic distortion isn't percieved by the ear as distortion at all.
What is the effect to a listener of adding a few percent HD to the waveform of a musical instrument, or group of instruments ?
It is to brighten the timbre of the instrument.
Since most of the 'distortion' products will be present in the undistorted signal, a similar effect may be obtained by adjusting the tone controls."

"I also contend that most of the apparent subjective differences that still exist between different audio amplifiers are not due to distortion at all but to slight differences in frquency response.
This point should recieve far more attention during design than it generally does.
The Human ear/brain combination is also very good at correlating impressions over time, so even slight bumps in the frequency response can become noticeable and even irritating eventually.
For example, when did you last see an amplifiers frequency response flatness specified as 0.01% ?. Plus or minus 1dB is more usual, which is 12%, and even 0.5 dB is 6%."

He futher goes on to say that IMD is the most objectionable distortion mechanism, and affecting "intelligibility of communication"

Best if you read the whole article - anybody able to scan this article in EW/WW June 2000, pp 440 - 447 ?.

Regards, Eric.


"
 
Disabled Account
Joined 2001
"You need to do your own rigourous testing."

Ah, not feasible or needed. It is perfectly easy to insure positive polarity from the source unit in order to reduce risk of their being an 'audible' problem IF their is one. Problems with recording polarity? Unavoidable.

"further supports my assertion that usual blind testing is inadequate"

However I must maintane much more trust in the blind testing that is feasible to perform, even though it is not usually possible to implement very tight controls, as would be required for a scientifically credible test. It is more accurate than careless sighted testing. Too many biases involved. Judjements altered. WORTHLESS conclusions. NO VALUE whatsover, excpet for psycholoagical effect and bedtime stories. I could go on to cite many more references to extend my prior links concluding the fallacy of subjective testing, but what is the point? YOu obviously do not care, or at least you seem that way. Logic is of no concern to you, only belief. The easter bunny can not be proven to not exist, kids say so. He MUST be real. Right? NO. Only to the person with the overactive imagination.

"It is perfectly substantiable because it is perfectly true."

Oh, then i will be awaiting the publication of the analysis for further peer review. After all, you can substantiate these claims, right?

Refer to the Pass vs. Yamaha amp comparison i referenced earlier. If your theory held, their could be no mistake. Hoever, in HIS environment on his speakers which he was very accustomed to, he could not pick out his own Aleph 1.3 set, from a Yamaha integrated when blinded. Neither could his mate, which was also native to the environment....and BOTH of them swore their would be no way they could not pick out the amps either. Bias, it does not discriminate.

"With practice and learning , you will be able to do this yourself at home reliably."

Learning? What? To believe in fairy tales? This has yet to be proven in ANY dbt performed as of yet.

"I also contend that most of the apparent subjective differences that still exist between different audio amplifiers are not due to distortion at all but to slight differences in frquency response"

Hmm...an article that agrees with my stance in most respects. Why was this posted by you? Low THD is irrelevant, and high output impedances are VERY relevant. Howver, the HIGH harmonic distortion components presented by amplifiers being driven often into clipping is a REAL issue and it's end result depending on if it's even or odd harmonic, most popular examples being SETs. Whether you find this coloration desirable is up to individual preferences, but it cannot be considered accurate. Again the reference to IMD is well known also, with this being a primary factor, when IM is low it is easier to localize individual sound occurences in the program material. Your point?

-Chris
 
<b>I guess aussies are just best at everything ;^)</b>

Yes. I know Eric is a reason to doubt that but......:D

<b>Guess we'd just have to do some A/B tests.</b>

I might get the chance to in the next year or so. I'd like to do some travelling and maybe even visit Canadia.
 
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Joined 2002
Lets face it folks, its all far too subjective...

As a Live sound engineer, I have worked with bands who say that the sound on the night at the gig was excellent, even though I had a hangover, and it was far too late at night to worry about it.

But, as far as the band were concerned, they sounded great, and the punters were happy, so perceptions were skewed.

Most studies on psychoaccoustics are carried out on students paid 20$ per hour who don"t give a F**k, so they are no more relevant than anything else...

If it sounds good, do it...

Al
 
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