ely
to be an artifact of aliasing which is a real problem in feedback FM).  Change the sine to
cosine in <code>(* amp (sin y))</code> and suddenly there's a ton of DC.  Fiddle with the
initial phase in that line, and there's always some choice that reduces it to 0.0.
Groan &mdash; it appears to be another "centering" problem, but I haven't found
the magic formula yet (a reasonable stab at it is: <code>-(phase-incr^(1-(B/3))</code>)).
</p>

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