[Trombone-l] Acoustics of brass instruments

[Daniel Pliskin]

>We talked about the hairclipper
>buzz recently.  That timbre indicates the waveform is a square wave.  We
>know intellectually a square wave is made up of a fundamental plus odd
>harmonics, with the 3X frequency at 1/3 amplitude, the 5X at 1/5th, etc.


My impression of a square wave is more clarinet-like.

A hair clipper may well have only odd harmonics, but it sounds more like a 
triangle wave, which also has only odd harmonics, but if I remember 
correctly, the expansion is more like:

fundamental/1 +third/3 + fifth/5 +…

Where a square wave is something like:

Fundamental/1 + third/9 + fifth/25 +…

So the triangle wave has considerably more high harmonics.

Of course, there are all sorts of duty cycle alterations, which also 
accentuate the higher harmonics.

Some day when I’m really, really, really bored, I’ll mike a hair chippers 
and check it out on an oscilloscope, for those inquiring minds out there.

DanP