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Re: maximum tatum (one tatum, two tata)
When I swept across the white keys about 50 years ago, I already expected
the tones like a spectrum of colors to orderly change step by step. So I
also imagined not to miss any tone. Obviously, parallel processing allows
to perceive many colors (tones) almost at a time. On the other hand, a
regular series of less than 40 light flashes (sound onsets) causes a
superimposed typical flicker (rattling noise). I was unable to count the
number of the together perceived tones. Meanwhile, I try to understand the
limitations separately.
Cortical limitation: If perception merely relies on distinction between
only two different colors, durations, or intensities, then I guess, a limit
of 10 Hz might be a reasonable estimate due to cortical sluggishness. In
simplifying words: Attention of the central nervous system is typically
limited to less than ten subsequent pictures a second. Conductors of an
orchestra might just be able to ramify these pictures.
Cochlear limitations: Even if the auditory snail is by far the fastest
organ of our body, I agree with John Bates in that the traditional notion
of hearing by spectral analysis in cochlea fails in case of rapidly
changing signals. Well, we are certainly able to hear at least 25-ms and
possibly 12.5-ms intervals between consecutive piano tones, and there is
evidence for perception of much smaller ITDs. Why does this not apply for
very deep or very high tones and also not for very high intensities? Aage
Moller wrote: 'Cochlear spectral filtering may be important for temporal
coding', and he referred to the pertaining phenomenon as 'synchrony
capture'. I called it the temporal aspect of spectral code. Divenyi
explained it best: The listener can use envelope analysis within similar
spectral bands.
Perhaps, most of so called cochlear limitations are actually set by
refractory time in the auditory nerve. This might be the decisive
bottleneck rather than limitations to cochlear mechanics, cochlear
amplifier or nuclei of midbrain.
Eckard
http://iesk.et.uni-magdeburg.de/~blumsche/AuditoryFunction.html