synth(
events,opts) ->buf,info/err
Render phoneme events into a sample buffer
Renders a list from phonemize or written by hand. The prosody pass fills
a missing dur or f0 in place. opts takes voice, the knobs and
rate, as say does.
info is { rate, dur, frames, events }; dur is in seconds. Returns nil
and an error for an unknown voice or an empty list.