Why use Pentax?

Started Mar 18, 2013 | Questions thread
bob5050
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Re: Bob
In reply to Gerry Winterbourne, Mar 23, 2013

Gerry Winterbourne wrote:

One thing that occurs to me, although I have no evidence for it, is that even if I can't distinguish high frequencies as such, the higher harmonics modify the shapes of the waves I can distinguish. If so, perhaps there's an analogy with high visual frequencies?

Not that I'm aware of, and it would be really surprising given that the cochlea essentially functions as a frequency separator--the brain then puts all the separate frequency signals back together again. Probably part of why one can mentally focus on specific tonal ranges/instruments within an orchestra. If you can't actually detect the high harmonic, there's nothing to re-assemble.

Found this rather detailed audio pixel-peep type analysis: http://www.davidgriesinger.com/intermod.ppt. His conclusion (slide 30) is that anything over about 23kHz is meaningless for multiple reasons, but principally because (1) recorded sources don't actually contain any signal higher than that that's louder than the medium background noise, and (2) the sound dispersion characteristics of a tweeter make it very improbable you're actually getting its signal unless you've very carefully positioned everything.

I'm not sure if it is strictly relevant but this post from The Online Photographer shows that we can perceive better resolution than our eyes ought to be able to pick out. http://theonlinephotographer.typepad.com/the_online_photographer/2010/01/how-sharp-is-your-printer-how-sharp-are-your-eyes.html

Interesting piece, relevant to this particular thread or not.

Visual perception is even more complicated than hearing, of course. AIUI, our eyes actually vibrate to a certain extent, and the resulting constant signal change at any particular point is much of what causes the nerves to fire. (full disclosure: been a long time since college, and the physiology of sight not somethng I ever really tried to keep up with). Be interesting to think that we have our own internal sensor-shift based AA going on ...

bob

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