These patches demonstrate how to use Pd's short-time Fourier transform objects,
rfft~ and rifft~, to do a variety of things.  The patches can be quite
expensive; the phase vocoder, for instance, requires an R10000 processor to run
at 44100 Hz.  By default Pd runs at 44100 Hz, but you can specify a different
sample rate on the command line, for instance:

pd -r 16000 09.pvoc.pd

On SGI, Pd will check whether your audio system is running at the correct
sample rate and will print out a warning if not.  On NT or W95, Pd's behavior
will depend on your audio driver.

Included in this directory are:

01.fftanalysis.pd -- does a windowed FFT analysis and resynthesis of a sine
tone, showing how to specify block size and overlap.

02.noisefft.pd -- Fourier analysis of white noise.  This patch also shows how
you can average power spectra over time.

03.denoise.pd -- using the technique from the previous patch, finds the noise
floor in a recorded sample and attempts to scrub it away.

04.shifts.pd -- tests the leftshift and rightshift "externs" used in the next
patch.

05.sheepgoat.pd -- tries to discriminate between "pitched" and "unpitched"
components of a sound.

06.sheepgoat2.pd -- another attempt at the same thing.

07.tinbell.pd -- a spectral flattener, which can make the sound of a large bell
turn into the sound of a tamtam.

08.convobros.pd -- spectral cross synthesis between two sounds

09.pvoc.pd -- phase vocoder

---------- after this point, the patches haven't been cleaned up -----------

10.phaselockedvoc.pd -- phase locked vocoder; see Laroche&Dolson in ICMC97 for
a discussion of something that works better than this.

11.pianorev.pd -- an attempt at a phase-coherent reverberation algorithm to
imitate the "piano reverb" obtained by putting a speaker under the sound board
of a piano and picking up the sympathetic vibrations.

12.sinedecomposer.pd -- estimate the frequencies and amplitudes of the
components of a sound

13.tracemaker.pd -- show how to use Pd to combine snapshots of a spectrum into
continuous spectral traces.

14.partialtracer.pd -- sinusoidal analysis/resynthesis of a time-verying sound.

15.waveformgrab.pd -- bash a sample into phase-coherent windows and make a
pitched resynthesis.







