[sdiy] Timbral musings

Mon Feb 17 22:31:54 CET 2003

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From: Stromeko at compuserve.de
Subject: Re: [sdiy] Timbral musings

>You can take another hint from how electric guitars are played: 
>distortion to my ears often comes to life only when you use it with 
>specific _intervals_, especially containing perfect 4ths (relating to 
>subharmonic scales, 3rd subharmonic), 5ths and 3rds (relating to 
>harmonic scales, 3rd and 5th harmonic). 

Not a valid example imho... the problem is because electric guitars are
polyphonic... and you are driving a polyphonic signal into a waveshaper
(usually a simple clipper).

The fourths, fifths, octaves sound the best because these intervals
more closely approximate a single (complex) monophonic waveform.

This is not 'harmonic' distortion anymore (which is pleasant sounding) its intermodulation distortion (which my dad used to say 'sounds like sh!t')

If you waveshape each individual note...then combine... any interval that makes musical sense will sound good (obviously half step intervals
are still pretty bad sounding...)

Agreed... with a standard guitar you need to play monophonic, or simple
integer ratios or you get the 'sh!t'effect.

Simply using a sine oscillator 
>for fundamental, third, fifth (these two possibly together) and fourth 
>and modulating the relative levels into an overdrive already gives 
>quite nice effects.

OK sounds good.

>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.
>Achim.

OK that sounds good too ;^P

H^) harry