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The jumpiness or high change of a signal is due to the higher frequency components in the signal. So if I have a sound signal that increases suddenly in amplitude, why doesn't the signal sound very high pitched at that point?

For example, if I suddenly knock on a door or hit something, the pitch doesn't sound very high, but the magnitude of the sound increases from 0 to a number very quickly.

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  • $\begingroup$ If you play a 1kHz sine and a 1kHz square wave, does the square wave sound very high pitched? $\endgroup$ – a concerned citizen Apr 17 '17 at 4:52
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    $\begingroup$ I think this is a great setup for an experiment. Set up your laptop with a microphone close to a door, start recording, and then knock on the door. Then analyze the data to see what the rise time actually is, and what's its spectrum look like. If you do the experiment and analysis, you can post your own answer here -- I'd be interested in reading it. $\endgroup$ – MBaz Apr 17 '17 at 13:29
  • $\begingroup$ I'd be as interested as @MBaz, and I think based on your observations, we can very much help you, then! $\endgroup$ – Marcus Müller Apr 17 '17 at 20:17
  • $\begingroup$ I would be as interested as MBaz and Marcus! $\endgroup$ – Dan Boschen Apr 19 '17 at 1:04
  • $\begingroup$ Thanks for the interest. It looks like a good experiment, but I'll have some free time when my finals are over :D $\endgroup$ – Goldname Apr 19 '17 at 1:31
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Pitch is a human psychoperceptual phenomena, which does not work the same way as a Fourier transform.

IIRC: Even if an FFT shows strong high frequency components in a short impulse or burst, the human ear-brain-system needs to detect roughly somewhere on the order of around 6 repetitions/periods/cycles of a periodic or pseudo-periodic acoustic waveform before communicating "I hear a pitch" to consciousness. (depending somewhat on, but nowhere near linearly with, frequency). A single or duple period of even a pure sinewave won't do it.

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  • $\begingroup$ Sorry, don't have a reference. I think I saw this in an audiology textbook I browsed in some library many years ago. $\endgroup$ – hotpaw2 Apr 17 '17 at 20:52

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