John Curl's Blowtorch preamplifier part II

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congratulations you can hear a 2 dB loudness difference
Congratulations, you never change, considering everybody as stupid !
Did-you imagine that, after a long life as a sound engineer, I'm not able to make the difference between a level and the 'structure' of a sound ?
Why don't, for a change, you try with your own ears, instead of using your *intellect* to listen ?
 
Esperado

I don't think my ears are special

I do respect the work of Psychoacoustic researchers, University Professors, textbook authors, peer reviewed journal publications...

... self proclaimed internet audio gurus - not so much


and I did put up a audio phase/polarity test - in fact badgered one prominent writer on audio to listen, converted him out of his "denial" position


I really don't understand your taking me as a personal enemy - I liked your early posts, still find some of value - I do however always question, point out technical error, things that don't fit into current EE or Psychoacoustics
and I believe I do qualify as a well read amateur on Psychoacoustics and have been employed for decades as a EE designing Scientific/Industrial Instrumentation from transducer interface through ADC, DSP, closed feedback loops over 50 feet of cable, designed analog and digital motion controls...

.. and have built a few audio projects - including a headphone amp that uses CFA output op amps - hardly a denier or enemy of CFA - just against the fanboyism you seem to be in middle of with respect to CFA
I even liked your mixing board example - for sound technical reasons it is a great use of the CFA property of loop compensation being a function of feedback impedance


John, you have thoroughly earned any personal animus from your internet persona - anyone not agreeing with you is a personal attack - no degree of technical argument is ever responded too
 
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Usually a recording engineer also is close to the live sound source. It is important to know what the live sound really sounds like of course.
Some people just appreciate music, and can live with MP-3 or its equivalent. Others, like myself, appreciate the 'sound of music' more, so that sound quality differences are what is paid more attention to. This is where MP-3, and even CD tends to fall apart. The latter emphasis helps when evaluating and designing hi fi equipment. Almost any playback system can produce 'music', but not the highest quality reproduction of music.
 
Are-you sure ? Yes, most of us cannot hear 18KHz sinus at normal power, but, cannot explain why, but i can hear the difference between a 9K sinus and a 9K square !
If so, it is down to non-linear distortion most likely in the transducers such as speakers, or maybe even in one's ears. For sure, most of us can't hear even the 2nd harmonic of 9kHz, and can't tell tonal difference between natural 9kHz fundamental waves no matter what shape............
 
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Usually a recording engineer also is close to the live sound source. It is important to know what the live sound really sounds like of course.
Some people just appreciate music, and can live with MP-3 or its equivalent. Others, like myself, appreciate the 'sound of music' more, so that sound quality differences are what is paid more attention to. This is where MP-3, and even CD tends to fall apart. The latter emphasis helps when evaluating and designing hi fi equipment. Almost any playback system can produce 'music', but not the highest quality reproduction of music.

You have just defined an audiophile in terms of you listen to the system not the music?
 
I don't think my ears are special
I do respect the work of Psychoacoustic researchers, University Professors, textbook authors, peer reviewed journal publications...

... self proclaimed internet audio gurus - not so much
jcx, my ears are not more special than the nose of a "nez" (perfume creators). It means just my *culture* in matter of sound, musical instruments, and music production is ...special. because all our individual cultures are unique, because no two people have the same life ... and the same soul.

Now, for the second part of your messages, Psychoacoustic researchers, if they exists, are just tying to put numbers on "average psycho", on my point of view. Their work can help, like Fletcher and munson's, but they cannot enter in our brains like music do and don't know the way I or an other is 'feeling' ;-)
Like nobody is able to say we all perceive the colors the same way.

University Professors, well, if you are talking about the guitar lessons of Larry Carlton, oh, Lord, yes, he knows what he is talking about. ;-)
For most of them, what did they produced, apart reproducing other ideas and words ? What I called 'intellectual' ;-)
Textbook authors ? It is not because something is printed that it has any added value, if you see what I mean.

"self proclaimed internet audio gurus", well do you really think i consider myself as one ?

Just I have a passion for music. So I have studied electronic, like a race car driver can study mechanic. I believe that I share with John Curl the experience to have been very close to musicians and instruments, PA systems, recording studios, and electronic design in the same time. With a difference, one was 70/30 and the other 30/70 when it comes to the pressure of our feet in the two worlds. And, ask him, we are not so many to had been professional in the both worlds.

I don't pretend to teach something, oh, Lord, not. I doubt of everything, including my own believes.
I would love to have your certainties.

Well about this matter of harmonics, I used sometimes to add in my recordings some bumps in the response curve of voices at 40 or 50 KHz. It change the sound, every body who was present at this time noticed. Now, is-it because it change the acceleration of the speakers, or our ears are more sensible to the fast peak changes than average values, or some kind of IM added at lower frequencies, I don't know.
But the volume answer, no way: we use faders in our mixing desks for the levels ;-)
As I said, just try it. I will be interested by your results, I'm not interested in any 'theory trying to demonstrate the contrary of what I had experienced myself.
 
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above ~7 kHz all you need to match are the fundamentals - the harmonics that make up the square wave could be reproduced with some error without affecting the fundamental and are "ultrasonic" so a few dB shouldn't make a difference as long as any nonlinearity, perhaps excited by peaking, doesn't cause nonlinear products in the "conventional audio" range

2nd order nonlinearity could make audible 2nd harmonic which wouldn't be masked
3rd order could affect the amplitude of the fundamental and should be limited to less than ~ 1%


I am not doctrinaire that "nobody can hear anything above 20 kHz" - but the evidence seems good that not many do, and even if found they don't hear much higher frequencies through the air, their ears - and I doubt any of them are 50+ year old males


but I do dismiss any claims not backed up with Psychoacoustically valid listening tests with blinding, controls - that is my line in the sand

train, construct artificial test signals, or listen for hours with "music I know well" - just do it blind, level matched and show statistical resolving power

publishing in peer reviewed journals helps too - its 3 decades since CD 44.1 and we don't have quality positive listening tests in the literature
the few "ultrasonic hearing" papers have been shown to suffer from "conventional audio" frequency differences due to nonlinear transduction, amplification IMD products or have bad statistics

if its so obvious it should be easy to fix this sorry (in apparently many audiophiles estimation) state of Psychoacoustic knowledge
 
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Do we know that the sinus and the square were not level-matched? And if electronically level-matched, there would still be a significant attenuation of harmonics by most tweeters.
Are our brains sensible to the efficient power or peak ? Is not our brain compressing / expanding continuously the perceived levels ? Filtering the bandwidth a little like a spectrum analyzer to extract informations were we concentrate (In space time and frequencies) ?
I will put an example in Photography. Look at a splendid sunset, and photography-it with a very high dynamic full frame captor. You can try everything that you want, no way to reproduce what you had seen. Your brain had compressed the all scene, and, in the same time, expanded details in the high lights and low lights.
 
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