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 a 300MHz Pentium 2 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.  In NT or W95, Pd's behavior
will depend on your audio driver.  In Linux Pd usually tries to set the rate
of the conversion hardware.

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.







