[PD] Spectral focusing

[eran at mx.kein.org]

Hello list,
After a few years of maxing I migrated back to PD about a year and a half
ago and haven’t looked back.
Now I ran into a stumbling block and I figured I turn to you for help:

I’m looking for a way to impose a harmonic spectrum on a non-harmonic
signal. I tried cross-synthesis with a harmonic signal, which is ok, but
what I’m actually trying to do is to “tune” a field recording, in a way,
so it can have harmonic relations to a live instrument.

I played with the pvtune~ object from fftease which is nice, but the
results end up sounding a bit autotune-ish. And I also tried driving a few
vcf~ filters with frequencies running from fiddle~/sigmund~ but the
fundamental from these objects is too erratic and it sounds very
unnatural.

Wishart describes in his book a technique he calls spectral focusing,
which relies on lpc. He says that lpc can be set to generate a filter bank
which is distributed evenly with respect to pitch, but I’m not sure I
understand what he means and how it can be done in PD. lpc seems to output
a set of amplitudes for the coefficients. Can I set the filters to
frequencies of my choice?

Any help with this would be greatly appreciated,
Zax