[PD] Sigmund~ and tracks.

J bz jbeezez at gmail.com
Wed Feb 9 17:41:57 CET 2011


Hi all,

I'm doing a piece with a viola d'amore (7 string viol) where [sigmund~] is
analysing the live input and feeding 48 tracks/partials to a bank of 48
[osc~] for resynthesis and a bit of jiggery-pokery, mainly reversing the
amplitudes so the quietest partials are the loudest and vice versa.

The viola is playing long(ish) single notes between 1-3 seconds and the
problem I am having is that when sigmund processes the partials they come
out rhythmicised/pulses which seems to be a combination of the 'hop' and
'npts' settings.  As the values for hop and npts get higher the pulses get
longer up until my current huge setting:
[sigmund~ -npts 65536 -hop 65536 -npeak 48 tracks]
when the partial frequencies balance out into steady lines.
I have also tried -hop 131072 which works too but trying that with the -npts
completely locks pd.

The problem I have now is that there is a significant delay between the
beginning of the processing in comparison to the viola and worse still is
the overlap after the viola has stopped playing.  Also the viola notes are
indeterminate so I can't just set a cutoff to sync the two together.  I
could use the input of the viola to gate the tail of the processing but I am
currently using a combination of [env~] and [lop~] so that as the performer
plays his amplitude controls the processing in reverse, so when he's loud
the processing is quiet etc.  I suppose I can add another layer on top of
the end

I am aware that the gap between the two sounding events is caused by the
huge window sizes I am using and that there may well be no way around this
to get the kind of sound from the processing I'm looking for, i.e. without
the pulses, but I am wondering if anyone has any tips and tricks I can apply
to try and bring the two sounds, viola and processing, closer together.  Or
ideally some way of achieving the smoother processing with lower npts and
hop settings. This is for a live performance btw.

All good wishes,

Julian
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