[sdiy] harmonics & vibrato

[Ken Stone]

This sort of problem does however surface in a different situation. When
simulating pipe organs, people want a "celeste" rank - a row of pipes that
is tuned 2hz above the normal rank. The easiest way to achieve this is to
use a frequency shifter, but the problem is the harmonics all get put out of
wack. Using a second TOS is not on, because 2hz is not maintained across the
spectrum. The only way to really get it right is to have an oscillator for
each note in the celeste rank. 

Of course, using DCOs, it is all a lot easier - two DCOs per note of polyphony.

Ken


>Tim,
>
>If you think about it, the mechanics of a violin vibrato is made from 
>the movement of the finger, back and forth on the string. This would 
>have a similar effect on pitch as placing the finger on another part of 
>the string to change the note (pitch). I would say, for the most part, 
>that each harmonic maintains its relationship to the fundamental as some 
>form of ratio. There may be some added components of sound I am not 
>aware of in the fast movement of the vibrato. Additionally, the 
>resonance of the violin body that is coupled through the bridge will 
>have an effect on the relative strength of the harmonics depending on 
>the particular pitch(es) being played. Any violin experts out there with 
>some added insight?
>
>Scott
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