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A really big can of worms

Soundmind you are really an old dog that can’t learn to sit, and clearly under your sun there are nothing new…

I gave you perfectly good examples of what could be causing the things we hear, but you didn’t really address any of them in your responses. Why? Is it because you know that you can’t argue against them? And put attention to that I said “could be causing” I have never proposed that what I am saying is the only truth like some others, but as long as I hear differences I have to seek answers.

“When TOTAL harmonic distortion is measured in tenths and hundreths of one percent, it doesn't matter how it is spread out. I believe that they are all inaudible.”

If you can’t hear it, then it’s good for you. BUT just because you can’t hear it you can’t sit there and say that it doesn’t matter. I have to trust my ears. I talked with my brother about this yesterday, and we compared this issue with the ability to hear the difference between different acoustical-guitar brands. I can hear the difference between a guitar with steel strings and one with nylon strings, and I can hear the difference between guitars of different size and shape. BUT I can’t hear the difference between different brands if they are of similar shape and size, but there are people who can do this and just because I can’t hear it I can’t say that it doesn’t matter…

“BTW, if you don't think errors in control systems are important, think again If an amplifier feedback system fails, the worst that can happen is it goes into spontaneous oscillation and blows up destroying a device which at most is worth a few thousand dollars and frankly its parts are worth only a few hundred. If an industrial controls system fails or the design is faulty, the damage to equipment and machinery can easily run into the millions …”

You know that I was referring to the error between the wanted output and the actual output in a control system, the error signal. But you respond by talking about money and system failure??? Money is NOT the issue here!!! If an audio amplifier goes into spontaneous oscillation it’s just a bad design and a competent electrical engineer would have corrected it for this, and if you have encountered control system failure because of faulty design from your part and lost a lot of money, bad for you.
(And I’m fully aware of that control systems can be unpredictable and cause problems, but that was not the issue here)

“I think 70 to 75 db S/N ratio for vinyl is a little optimistic. I think realistically, at least for most of what was produced in the real world, 55/60 is more like it.”

What I said was that “vinyl works despite the S/N-ratio of around 70 - 75 dB at it’s best”. “at it’s best” means that this figure is not reached all the time. And there has been development in this area too in resent years resulting in much lower surface noise and hence better S/N-ratio. I have a couple of records with I think surpass 75 dB S/N-ratio, maybe I should make some measurements… Hmmm
BTW Vinyl is still produced and most of it surpasses those records produced in the 80’s regarding to technical specifications.

“So at what threshold percentage as a function of f and N does each of these harmonic distortion components become audible?”

Soundmind you are again showing your incompetence and inability to grasp the whole picture by asking for a blunt number of distortion %. The answer is that it depends! I recommend you to read

“Just detectable distortion levels” by James Moir Wireless World Feb 1981

“Some Defects in Amplifier Performance Not Covered by Standard Specifications” by Norman Crowhurst. JAES Oct 1957

“Do your ears deceive you?” by Tom Farrimond. Practical Hi-Fi Jan 1980

“Inaudible High-Frequency Sounds Affect Brain Activity; Hypersonic Effect” by Oohashi et al. The American Physiological Society.
And the AES preprint # 3207 September 1991

“Capturing Music: The Impossible Task” by James Boyk. Seminar at the University of California, San Diego April 2004

When you have read these papers you should be aware of that it depends on frequency, level, what you are listening to (i.e. how long, in time, are the high level peaks in the program material) and the order of harmonics among other things. So you just CAN’T just give a blunt number, but maybe it works in your simplified world.

The article by James Moir says most of it, so if only care to read one, read that one.

This far we haven’t talked about the interactions between the amplifier and the loudspeakers because of EMF, and then there are other even bigger cans of worms we haven’t touched yet. It’s interesting to se that with every step of “development” we end up with less linear devises, with DHT-tubes being the most linear device ever made. I know that tubes have their problems and limitations and that bjt’s with local feedback can have better measurements, but the listening impressions can tell another story…



Enjoy Creating / Mad Man Harju

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