Graham,

I've struggled with the Spectral Data opcodes to no avail. However, my
interpretation of the manual is that the useful output from the group are
the k-rate outputs from
specptrk and
specsum
These produce a pitch estimate of the wsig and return the signal strength at
krate. You cannot, as far as I can make out, use the operators to manipulate
the spectrum of the incoming signal for output unless, as you suggest, you
write additional opcodes to add to the group.

Let me know how you get on. I could only get CSound to crash when using
these opcodes.

Best wishes,
Richard.

> However I don't see an opcode convert the wsig back to an audio signal.
How
> is this done?  I can see that pvoc can be used for additive synthesis, but
> takes a file as input, not a wsig.



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