Jinx wrote:

> If you want to mix square wave frequencies, put each through its
> own tone control before you mix them.

  Perhaps I forgot to mention in reference to PWM that to mix tones, you
just generate the "analog" values, then add them and feed to the PWM
algorithm.

  The phase accumulator version of the PWM doesn't require
synchronisation with the waveshape generating algorithm either - you
just determine your "analog" value whenever you want, and feed that as
"current" to the phase adder.

> A triangular wave is reasonably close to a sinusoidal wave and is
> quite a pleasant sound.

  This is an example of a "rule-based" synthesis.  A phase accumulator
generates the phase value, which is negated if the MSB is set.  Instant
triangle wave!
--
  Cheers,
        Paul B.