John Curl's Blowtorch preamplifier part II

[dimitri]

Hello Scott,
On 125th AES Show (2008) Keith Johnson presented a master class Sonic Methodology and Mythology
Unfortunately I couldn't find any recorded information from this master class on the Net. The letter from Keith is cited, where he explained what was presented.
I attended this master class. Essentially he constructed low-bandwidth PLL system and analyzed the error signal (listened). Different optical/copper digital cable in the system revealed in different PLL error signal. Different power cords and their placement also gave different signature in PLL error.
More about Keith can be found here

[john curl]

Keith Johnson is a very sharp designer and one of my fiercest competitors. I fear him more than most other engineers, as far as winning design contests go. Known and respected his work for the last 44 years.

[scott wurcer]

Originally Posted by dimitri

Hello Scott,
On 125th AES Show (2008) Keith Johnson presented a master class Sonic Methodology and Mythology
Unfortunately I couldn't find any recorded information from this master class on the Net. The letter from Keith is cited, where he explained what was presented.
I attended this master class. Essentially he constructed low-bandwidth PLL system and analyzed the error signal (listened). Different optical/copper digital cable in the system revealed in different PLL error signal. Different power cords and their placement also gave different signature in PLL error.
More about Keith can be found here

“We don't have DSP to degrade the signals.”

A broad brush one might say or maybe a casually dismissive comment from someone who should know better.

BTW sorry if I offend anyone but I find his Reference Recordings RR11 excruciatingly boring.

[john curl]

Nonetheless, I fear him a lot more than I fear you! '-)

[Esperado]

Originally Posted by john curl

Nonetheless, I fear him a lot more than I fear you! '-)

One thing is for sure, if we organize a gentleman's contest, Scott has nothing to fear from you.
And as the technical quality of an engineer is only a reflection of his personality, you can conclude as required.

[Telstar]

Originally Posted by Kindhornman

Christophe,
I think that we have to look way beyond the simple steady state response of the speaker. We need to look at the transients response or rise time of the signal and how that relates to the original waveform that we are trying to reproduce. I'm way off topic so I will just shut up now.

There was ever an in topic in this megathread?

I think you nailed the problem: look into the time domain and ignore nyquist.

[Telstar]

Originally Posted by scott wurcer

“We don't have DSP to degrade the signals.” .

Well, it's true
Unless you do it in the only digital source before d/A conversion.

[Esperado]

Originally Posted by Telstar

look into the time domain and ignore nyquist.

Yes about Nyquist: most of the loudspeakers have amazing group delays :-)
I'm pretty sure that our ears do not care too much of phase relationship between the harmonics of a sound; tweaked anyway by the distance and speed of air propagation.
But i believe our ears do a sort of 3D FFT map where the third dimension is, indeed, time.(My ears are very sensible to the level of the first micro seconds.)
And filter on the fundamental and multiple of its to separate the instruments. With some sort of pass band filter around 1/3 oct around the fundamentals, like do some compression algorithms.
I'm surprised how little had been done, on the scientific and experimental side, to figure out the way our brain processes to listen.

[SY]

Originally Posted by Esperado

But i believe our ears do a sort of 3D FFT map where the third dimension is, indeed, time.

What are the other two?

[gk7]

Originally Posted by Esperado

...
I'm surprised how little had been done, on the scientific and experimental side, to figure out the way our brain processes to listen.

A lot of work has been done, but mostly in the fields of medicine and biology, so it´s conveniently ignored by audio engineers...