John Curl's Blowtorch preamplifier part III

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So when you adapt to a sound, like when entering a room or moving position or focusing on a particular person for example, that's not psychoacoustics? Or masking, ignoring reflections etc?

It depends, but the auditory event as reaction to a sound event is the interest of psychoacoustics.
Psychological factors, for example bias effects like confirmation bias, are not examined in psychoacoustic experiments.

I know Wikipedia isn't the be all and end all but this is from the entry on psycho acoustics <snip>

The german Wikipedia entry reflects what I've (briefly) mentioned above and before.

In your example there is the "citation needed" included that IMO should be valid for the paragraph in total and overall the paragraph reflects more casual talk about "......" .

Of course, sometimes the boundaries are flexible, for example in the case of ASA (auditory scene analysis) or the experiments for the "inattentional deafness".
 
...Expectation bias...

What does the term expectation bias mean, in your personal language?

A formal definition may be found at:
List of cognitive biases - Wikipedia

...but it doesn't make sense the way you seem to be using the term.

Usually, people get called out for misusing scientific terms and loosely using the misused terms along side proper scientific terms. Maybe your idea is to repeat the misuse in every post so people get used to it and accept it as real? in that case why is your nonsense any better than what many people think of Max's?
 
If we are looking for a way to describe why people may hear what they expect to hear in some situations, there is probably some existing psychological insights that can be applied to it. The term 'expectation bias' is not part of it, despite however much some would like it to be.

How about 'priming'? How about the focusing illusion? Confirmation bias?

I would suggest a hypothesis where priming prepares one to hear what is expected, and once heard focusing takes over to make a particular aspect of the sound of something seem much more important than it is to the overall sound. Then confirmation takes place. However, there is not supporting research specifically for 'hearing what one expects to hear.'
 
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If you did use confirmation bias in error, you were probably close enough to be understood, and essentially technically correct. Could be I missed it too.

My problem here is not with you personally, of course. I don't want to fight either. It's just that I think we in engineering have got too far away from a scientific understanding of psychology, and that makes us spout nonsense sometimes while feeling self-confident we are still well within the bounds of engineering expertise. It is the same basic mistake others are called out for making here when they do it with EE and physics terms. So, we are hypocritical about that if we don't at least try to hold ourselves to the standards we set for others.
 
Mark seems overly keen on reinforcing your bias that you are not susceptible to expectation bias or confirmation bias and probably others which are evident in your posts.

If you did use confirmation bias in error, you were probably close enough to be understood, and essentially technically correct. Could be I missed it too.

See above, as I hope you can see I was trying to make the point light-heartedly because Bob doesn't seem to be able to accept the possibility.(I think he called it psychobabble) I later made the point that you were the expert on cognitive biases as well 😉 We have a different way of expressing ourselves, I'm kind of getting used to your pedantry and try to take it into account 🙂
 
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Joe, you have mentioned possible problems of class AB amplifiers when driving a complex inductive load. I was very skeptical to this, as I have had no bad experience like that and operational class of the well designed amplifier did not seem to have any special effect to clean complex load driving ability, to me.

However, something strange happened to me. I was measuring 2 preamplifiers, with basically same circuit design (complementary differential JFET input + folded cascode VAS + output stage) which were different only in the output stage circuit.

Preamplifier “A” has a diamond buffer based output stage, with output impedance 50 ohm (series resistance). Preamplifier “B” has a conventional NPN-PNP simple EF output stage, with output impedance 50 ohm as well (series resistance).

Both preamps measure almost identically into 10k resistive load and both are able to drive 50 ohm load with low distortion, “B” being little worse but still keeping THD in order of 0.001%.

Now, I tested both “A” and “B” with a link level output transformer, which a primary Rs = 40 ohm, Ls = 4H, secondary Rs = 70 ohm and secondary Ls = 4H. This transformer has of course increased distortion at low frequencies and I have measured it dozens of times.

But, what happened now. Though preamp “A” shows “standard” distortion plots with the transformer, preamp “B” has enormous rise of distortion numbers. A reminder, it drives a resistive load down to 50 ohms with no problems.

Attached are circuits of output stages “A” and “B”, measurements of distortion (at 50Hz, 200Hz and 1kHz) into link transformer with preamps “A” and “B” and also a measurement of the suspicious preamp “B” into 50 ohm resistive load.

Anyone with a meaningful explanation?

P.S.: 1V is the input range limit in these measurements
😎 🙂

measure Z vs Freq of transformer.

THx-RNMarsh
 
Not to look like a total moron, but hey why not.....

What about just taking off the speaker wires that were in use then re installing the same wires within a few minutes?

There was still a ‘settling’ period after turning it back on........is there a optimum ‘state’ that gets disturbed by such an action?

What "action" ? Time? Wow you really believe this? What has changed with the wire in a few minutes. This nonsense would mean that a system will sound different every new day from just sitting there. You just shot to hell any vestige of belief in your hearing abilities.
 
It happened to be the DC offset issue, as BV has suggested. "B" had output DC about 50mV, "A" 0.2mV. DC offset made a shift on the trafo transfer curve.
what affect would a small dc on amp output have on speaker distortion? Is there also a high sensitivity to any dc on output.

At least one person i know has added a dc bias to his driver to get minimum acoustic distortion.

-RNM
 
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What "action" ? Time? Wow you really believe this? What has changed with the wire in a few minutes. This nonsense would mean that a system will sound different every new day from just sitting there. You just shot to hell any vestige of belief in your hearing abilities.

Everything changes from one moment to the next. It is called entropy. Take a piece of lead, any size or shape, and it will sag under its own weight. Same thing will happen to a lump of glass, only a bit longer. A sound system will change from day to day, and that is a surety. Whether or not you can hear or measure the change is irrelevant, as entropy is relentless, and like this thread, unrelenting.

tapestryofsound
 
Everything changes from one moment to the next. It is called entropy.

Yes, but there always could be non-entropic local processes. Life is an example, Gibbs function (free entalpy) in chemistry is another one. So it is not obvious your audio system is affected by the Universe Global Entropy, and if an increased entropy correlates with a worse or better sound.

Having some fun, as usual :rofl:.
 
Yes, but there always could be non-entropic local processes. Life is an example, Gibbs function (free entalpy) in chemistry is another one. So it is not obvious your audio system is affected by the Universe Global Entropy, and if an increased entropy correlates with a worse or better sound.

Having some fun, as usual :rofl:.
Yes, the miracle of electrons colliding in cyberspace ......... interesting, why does a sound system when it settles in always sounds better - never been able to understand THAT one 😱

tapestryofsound
 
Everything changes from one moment to the next. It is called entropy. Take a piece of lead, any size or shape, and it will sag under its own weight. Same thing will happen to a lump of glass, only a bit longer. A sound system will change from day to day, and that is a surety. Whether or not you can hear or measure the change is irrelevant, as entropy is relentless, and like this thread, unrelenting.

tapestryofsound

Everything changes, whether you can hear it or not is the only relevant issue. If your amp sounds different daily its garbage, same with the rest of your system. And if this actually happened it would makes any atempt at improvement futile.
 
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