[sdiy] Ring Mod

[rburnett at richieburnett.co.uk]

There are a couple of DAFX papers discussing modelling the quirks of 
real diode ring modulators:

http://legacy.spa.aalto.fi/dafx08/papers/dafx08_29.pdf

http://recherche.ircam.fr/pub/dafx11/Papers/66_e.pdf

The short story is that it's *MUCH* easier to just do a simple 
multiplication operation in a digital synth and call it "Ring 
Modulation" because modelling a real diode ring modulator correctly 
takes significantly more effort, and it's likely that relatively few 
people actually know what a real diode ring modulator should sound like 
anyway.

-Richie,