The character of the click
There is no character at all in the click, as generated. The click is an impulse, and certainly that impulse contains all frequencies in equal proportion right across the audio band. It is as pure and characterless as truly random white noise, the type of static noise you hear between stations on an FM radio.
Originally Posted by weaver
Therefore as generated*, the impulse I've used has definitely no pitch, because it has no resonance generators and to sustain a pitch (a note). You have to have some sort of resonant system generating and sustaining the pitch. (A musical instrument is nothing more or less than a resonator in the same way that an empty wine bottle is a resonator and produces a pitch when blown across).
It is of course a trivial matter to put the click through a spectrum analyser and have a look at its spectral make-up. However - and this is important to bear in mind - you are hearing the click through your sound card and speakers/headphones as you cannot sense the click directly in your brain (as yet). So your perception of the click is the digitally generated clip mixed with the resonance characteristics of your speakers. Remember the box in the box in the box idea? The clean, dry click takes on the character of the speaker box (and drive units/crossover) and is being reproduced in your listening room - another box. So it is entirely possible that to your ears, with your speakers in your room that the click has some sonic character, but this is not inherent in the click itself for sure. So the very evident twang in the reverberation tail in Clips 11, 11A and 12 is solely that of the room modifying the characterless click.
* Note: when the repetition rate of the click starts to become very frequent, that is, very many times per second, it may well take on a pitch, but this is not relevant at this point. I've shown that even when there is a gap of a second or two between the clicks, there is still a definite audible character in the reverberation.
Alan A. Shaw
Harbeth Audio UK