John Curl's Blowtorch preamplifier part II

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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
 
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.
 
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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.
 
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.
 
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I perceive what I perceive. At least that. While I cannot hear as extendedly or as acutely as I could 30-40 years ago, I am self trained to still hear differences in audio products that may, in fact, be subtle, and little use to many others. I started off in life better at this than most, and instead of becoming a superior musician, I became a superior listener of musical instruments and musical playback systems. That is one useful attribute to someone who designs audio equipment. As the 'specs' do not reveal everything, and even advanced measurements often run into dead ends, it is necessary to know when you have really made a successful design, and when you have only made a mediocre one, that will last only a short time, and be forgotten.

Almost every time that I left out the IMPORTANT ingredient of ATTENTION TO DETAILS, coupled with not seriously listening to the audio product under development, I have failed (big time to me) in the marketplace.

I have actually gotten too confident, a number of times, and fell flat with both customer and audio reviewer acceptance, with NOTHING ELSE changed in the equation. Not the appearance of the product, not the advertising of the product, and not the promotion of me associated with the product. I learn from my mistakes, and I am here to advise others to avoid my mistakes that I have made in the past.
 
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