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In Reply to: RE: "Ordinary" magnet wire posted by kurt s on October 29, 2010 at 04:40:55
"It has been proven by two methods: a 7 KHz square wave fidelity test, and a 6 usec narrowest audible time delay test from left ear to right ear. Both show a same approximately 100 KHz to 200 KHz extended brain processing. One shows that hearing fidelity needs to go beyond the limit of "20 KHz" for the spacial fidelity to finish up, between ears that is beyond hearing but is not beyond brain processing speed in comparing signals of both ears delayed from one another.
Do you have a reference to the 7 kHz square wave test?
I don't believe you can equate delay sensitivity of 6 microseconds to bandwidth. For example, the bandwidth of 44.1/16 PCM is limited to 22 kHz, and an apparent time resolution corresponding to the interval between consecutive samples of 22.7 microseconds. However, there is sufficient information to further subdivide this period by a factor of 65536, which yields a time resolution of 346 picoseconds. One can easily see subsample pulse resolution by playing around with an editor and doing a combination of upsampling, downsampling and shifting.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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Hi
I don’t know if it is the same work but I did some consulting for Gary Kendall at Northwestern U once, who was investigating “stereo hearing” and he commented that in the investigation he did, that some people were able to detect an inter-aural difference corresponding to one wl at 200KHz.
Now, in questioning, he explained that was a time difference one detected and NOT a reflection on the bandwidth of ones hearing.
It was his finding that with the equipment of the day (in the early 90’s) that a sampling rate of 200KHz was sufficient to capture what we could detect (by monitoring brain waves) if not consciously hear. Some of the hf things seem to involve a brain response but no conscious awareness of it, that is to say you register a sound physiologically but you don’t hear it per say. That is different than hearing loss where you don’t register the sound or hear it.
Fwiw, to reproduce a square wave well enough that it looks essentially perfect on an oscilloscope, the system needs a bandwidth that extends from about 1/10 to about 10X the fundamental F.
Best,
Tom
Actually, it was different work done by Kunchur that sparked the debate that I recall. While his experimental work may have been exemplary he got thoroughly roasted for his conclusion that the ability to hear a 6 microsecond delay proved that more than 20 kHz bandwidth was required.
When I last tried, I didn't hear a difference between a 7 kHz sine wave and a 7 kHz square wave that had been band limited to 22 kHz, but it wasn't a serious effort. I once could easily hear a 21,000 cps sine wave. but almost 50 years later it takes a good day to hear 15,000 Hz.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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