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#X text 176 446 is signal power and "m" is mask.;
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#X text 175 464 (zero if s < m).;
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#X text 483 212 number of;
#X text 491 227 frames;
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#X text 521 133 hop size (analysis;
#X text 546 149 period) in msec;
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#X obj 235 258 expr 1/($f1+1);
#X text 134 17 calculate a mask using N msec of background noise;
#X text 43 354 current power (for each channel);
#X text 367 430 average the current power into the last mask to get
the new mask. The new value is weighted 1/n on the nth iteration.;
#X text 390 312 weight to average in new power to mask;
#X text 11 203 loop counting to desired;
#X text 78 219 number of frames;
#X text 72 39 This loops for "make-mask" milliseconds \, averaging
power in each channel over that amount of time. This is done by a moving
average whose weight is adjusted to average each new value equally
with each of the accumulating ones.;
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#X restore 132 203 pd calculate-mask;
#X text 91 98 real Fourier transform;
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#X msg 357 80 \; pd dsp 1 \; window-size 1024;
#X text 193 355 ... but not less than zero;
#X text 101 561 real inverse Fourier transform;
#X text 196 498 normalize by 2/(3N) where N is window size;
#X text 168 332 current power ("s") minus level-adjusted mask ("m")
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#X text 156 175 compute power (call it "s") in each channel;
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#X text 179 426 compute sqrt((s-m)/s) where "s";
#X text 296 204 <- subwindow calculates noise mask;
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#X text 15 8 calculate Hann window table (variable window size) and
constants window-hz (fundamental frequency of analysis) \, window-sec
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#X text 106 293 noise;
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#X text 113 252 read a sample;
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#X msg 31 322 \; read-sample ../sound/voice.wav;
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#X text 204 270 masking;
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#X text 270 247 sample duration \, msec;
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#X text 580 83 filtered noise;
#X text 105 15 TEST SIGNAL: looped sample plus noise. The inlets control
amplitude of each in dB.;
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#X restore 30 340 pd test-signal;
#X text 18 293 sampler;
#X text 302 294 calculate noise mask;
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#X msg 320 316 \; make-mask 2000;
#X msg 196 315 15;
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#X text 25 14 This table (1010-mask) is the average power measured
in each channel of the spectrum \, presumed to represent the noise
floor.;
#X restore 320 440 pd mask-table;
#X text 32 270 amplitudes (dB);
#X text 19 36 This patch attempts to scrub the noise floor from a sample
in two steps. First using the "make-mask" message (which is caught
in the "fft-analysis" window) \, you estimate the background spectrum.
You would normally do this at a moment when only the background noise
is audible. Then \, turn on "masking" (to 15 by default \, but try
other values) and the patch will try to clean the background noise
out of a signal.;
#X text 19 134 For this demonstration \, you control the amplitudes
of a looping sample and a filtered noise source. Normally you'd hit
"calculate noise mask" with only hte noise turned on \, then turn both
the noise and the sampler on \, and also "masking" \, to see if the
patch can clean the noise out of the signal. Open the "fft-analysis"
window to see the algorithm \, or the "insample" window to change samples
\, or "mask-table" to see the current mask (the average signal power
of the noise to clean out of the signal).;
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#X text 12 125 WEBSITE http://crca.ucsd.edu/~msp/;
#X text 12 105 AUTHOR Miller Puckette;
#X text 12 85 LIBRARY PDDP;
#X text 12 5 GENRE tutorial;
#X text 12 45 LICENSE SIBSD;
#X text 12 145 HELP_PATCH_AUTHORS Jonathan Wilkes revised the patch
to conform to the PDDP template for Pd version 0.42.;
#X text 12 25 KEYWORDS signal;
#X text 12 65 DESCRIPTION denoiser;
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#X text 7 2 denoiser- Related Help Documents;
#X text 19 37 Links:;
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