[sdiy] harmonics & vibrato - late response

[Dave Krooshof]

>Yo,
>
>Here is a ponderance: when a violin string is being
>played with vibrato, how are the harmonics being
>affected? do they change at the same frequency
>difference as the fundamental, or do they proportional
>to their ratio with the fundamental?
>
>To put it another way: If the fundamental is changing
>1%, does the 2nd harmonic vary 1% or 2%??
>
>Hey Scott,

>Well, as the finger moves back and forth it shortens
>the effective length of the string. The harmonics take
>less of a fraction of the length of the strng per
>wave, so it follows that the shortening would have a
>greater effect on the harmonics. Does that sound
>right?

=-= tr

Nope, wrong and right.
if you'd only look at hertzes, linear, you're right. but
sound/pitch is logarithmic, so the pitches of the
overtones do not get out of tune at all.
A 1 cent of a semitone rise of the fundamental
causes a 1 cent of a semitone rise on each overtone.

However.... The stiffness of the fleah and skin of the
violinist finger will vary while vibrating. This means
that certain overtones will reflect deeper or less in to the
skin, so the string will appear to be virtually longer or shorter
per frequency. Also, dampingsfactors will vary.
Think of these as changing impedances.


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