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Subject: Harmonic Bias Source

From: "Tkacs, Ken" <ken.tkacs@...>
Date: 2000-04-15

It's true that to work with "true" additive, you need to be able to specify
the phases of the partials, but I'm figuring you'll never get that close
with analog. Still I think you can get damned close (the ear isn't real
sensitive to phase in general), ∗provided∗ that any sounds you mix in to be
pseudo-partials of your fundamental oscillator are sines. That's why you
can't make a complex divider-based module for this---you get square waves
instead of sines and the ear will always hear them as separate pitches
because each has its own harmonic series.

You could devise some kind of divider-based pseudo-additive module if you
could find a good square-to-sine wavehaping circuit (hopefully cheap &
simple because you'd need a bunch of them). In all my wanderings, I've only
found one square-to-sine converter (usually sines are derived from the more
similar triangle waves), and that was in a data sheet for a shift
register... wasn't a real clean sine, I think, and it required two chips and
16 precision resistors per converter, which starts to get to be a lot.