[sdiy] Timbral musings

[harrybissell]

jhaible wrote: <snip>

> Yes, and this intermodulation sounds great if the fouths or fifths are not
> perfectly pure: Some of the intermodulation products are in the sub audio
> range, and they act like a LFO modulation of the waveshaper function ...

This is semi true. On a guitar they are equally tempered...and as the interval
of fifth and fourth are inverse (meaning a fifth up is a fourth down...) the
detuning is the same.

OTOH guitar strings are considerably non-harmonic... the overtone series is
quite sharp (maybe they should be called guitar-bars rather than strings... but
then
all the guitarists would like to go there to get drunk...  ;^)

These sharp harmonics make the IM products pretty obnoxious. Moral... don't
waveshape polyphonic guitar unless you do it on each sting separately... or if
you
use a global waveshaper, stick to octaves, fourths and fifths. If not you get
pure mud
(which some may argue they want...)

Guitar (equal tempered) thirds usually do not work through a waveshaper
(clipper)
at all...

(this info relates to Guitar as sound source... with VCOs you could make pure
thirds...)

H^) harry

>
>
> > >Another overdrive trick that might work with some waveshapers as well
> > >is to start with a harmonically rich waveform that still has a strong
> > >fundamental. As you drive it, it actually sounds cleaner as it
> > >approaches a square wave.
>
> And if you drive a soft clipping VCF (or VCA) with saw waves, these
> are rounded and loose some of their upper harmonics, too. That's
> why some filters sound "fatter" that others, even if their small signal
> behaviour (poles ...) is identical.
>
> JH.