[sdiy] granular synth on AVR or Ucontrollers??

[Olivier Gillet]

Granular synthesis from samples on a modest MCU is possible - the WTPA does it.

Auduino is labelled "granular synthesis" but it really is a variant of
the CZ-101 style filter emulation
(http://en.wikipedia.org/wiki/File:Casio.CZ101.resonance.png) or FOF.

Your idea would work with certain conditions... Especially for 2 you
need a smooth envelope to "cover up" to avoid the high frequency
content when a sine wave is brutally turned on / off at the top or
bottom of its cycle. The biggest challenge is to come up with a set of
parameters that has an interesting range. If you start offering
controls for burst frequency, burst randomness, carrier tone
frequency, carrier tone frequency dispersion, carrier tone
waveforms... you end up with a large parameter space but most
combinations are totally worthless.

You can get interesting sounds by triggering "windowed" bursts of sine
or triangle waves, with some probability law dictating the dispersion
of the sine wave from a central frequency ; and the regularity/density
of the bursts. Can make interesting "noises" - rain, wind blowing,
dark machine noises - but nothing I've heard of that that couldn't be
achieved with traditional modular synthesis techniques (noise through
high-Q filters, noise sent to VCA, noise -> S&H ->  low-pass filter).

In any case, before ever thinking of MCU, etc, try your idea with a pd
patch or a csound orchestra to make sure it is musically relevant and
has the right parameter space.

Olivier