From 57045df5fe3ec557e57dc7434ac1a07b5521bffc Mon Sep 17 00:00:00 2001 From: Guenter Geiger Date: Mon, 29 Jul 2002 17:06:19 +0000 Subject: This commit was generated by cvs2svn to compensate for changes in r58, which included commits to RCS files with non-trunk default branches. svn path=/trunk/; revision=59 --- pd/doc/3.audio.examples/45.envelope.follower.pd | 101 ++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 pd/doc/3.audio.examples/45.envelope.follower.pd (limited to 'pd/doc/3.audio.examples/45.envelope.follower.pd') diff --git a/pd/doc/3.audio.examples/45.envelope.follower.pd b/pd/doc/3.audio.examples/45.envelope.follower.pd new file mode 100644 index 00000000..0c3de2b4 --- /dev/null +++ b/pd/doc/3.audio.examples/45.envelope.follower.pd @@ -0,0 +1,101 @@ +#N canvas 64 77 982 581 12; +#X text 759 566 updated for Pd version 0.26; +#X text 67 8 ENVELOPE FOLLOWERS; +#X text 17 28 The env~ object reports ths RMS signal level over the last 256 samples (by default) or any other power of 2 that's at least twice the block size. The analysis is done in an overlapped fashion so that results appear every N/2 points if N is the analysis window size. So the larger the window \, the stabler the result and the less frequently it appears. Computation time doesn't depend heavily on N.; +#X text 471 28 Envelope followers are frequently used to detect attacks and periods of silence. (There are fancier attack detectors out there \, though.) Here is a simple threshold-based attack and rest detector.; +#X obj 152 160 dbtorms; +#X floatatom 75 142; +#X obj 75 165 osc~ 440; +#X obj 75 188 *~ 0; +#X obj 75 211 env~; +#X floatatom 136 216; +#X floatatom 152 137; +#X msg 219 155 \; pd dsp 1; +#X obj 87 307 t b f; +#X floatatom 87 330; +#X obj 94 385 pack; +#X text 198 215 note 3.01 dB difference between peak and RMS amplitudes.; +#X obj 94 408 route 0 1; +#X obj 94 431 > 55; +#X obj 139 433 < 45; +#X obj 94 454 sel 1; +#X obj 139 456 sel 1; +#X msg 16 494 1; +#X msg 45 494 0; +#X obj 94 494 print attack; +#X obj 87 365 != 0; +#X obj 517 267 t b f; +#X floatatom 517 290; +#X obj 524 348 pack; +#X obj 524 371 route 0 1; +#X obj 524 404 sel 1; +#X msg 458 525 1; +#X msg 488 525 0; +#X obj 517 326 != 0; +#X obj 547 290 < 45; +#X obj 542 441 timer; +#X obj 600 371 sel 0; +#X obj 616 496 sel 0; +#X obj 542 487 sel 1; +#X obj 542 528 print rest; +#X obj 542 464 > 1000; +#X text 125 330 state -- 1 if waiting for low threshold \,; +#X text 151 345 0 if we've attained it and now want the; +#X text 180 359 high one.; +#X text 165 408 route the RMS value according to state; +#X text 191 435 if off \, 55 dB means attack. If on \, 45; +#X text 192 456 dB or less means state changes to off.; +#X text 106 279 ATTACK DETECTION; +#X text 515 244 REST DETECTION; +#X text 590 288 Here we always will test RMS against a low value; +#X text 615 305 but as before we route the result according to; +#X text 637 322 our state \, 1 if "resting" \, 0 if not.; +#X text 645 368 regardless of state \, when RMS isn't low; +#X text 667 383 reset the timer; +#X text 691 511 RMS isn't low enough.; +#X text 602 403 If we're not in rest \, and the RMS is low \,; +#X text 626 419 check elapsed time sinse RMS last wasn't low.; +#X text 613 461 If more than 1 second \, report a rest.; +#X text 664 495 If we're at rest \, pop out of it when; +#X text 471 94 Both detectors are state machines with two states \, on and off. If on \, a test is run to determine whether to turn off \, and vice versa. The tests are run at each output of the rms~ object.; +#X connect 4 0 7 1; +#X connect 5 0 6 0; +#X connect 6 0 7 0; +#X connect 7 0 8 0; +#X connect 8 0 9 0; +#X connect 8 0 12 0; +#X connect 8 0 25 0; +#X connect 10 0 4 0; +#X connect 10 0 11 0; +#X connect 12 0 13 0; +#X connect 12 1 14 1; +#X connect 13 0 24 0; +#X connect 14 0 16 0; +#X connect 16 0 17 0; +#X connect 16 1 18 0; +#X connect 17 0 19 0; +#X connect 18 0 20 0; +#X connect 19 0 21 0; +#X connect 19 0 23 0; +#X connect 20 0 22 0; +#X connect 21 0 13 0; +#X connect 22 0 13 0; +#X connect 24 0 14 0; +#X connect 25 0 26 0; +#X connect 25 1 33 0; +#X connect 26 0 32 0; +#X connect 27 0 28 0; +#X connect 28 0 29 0; +#X connect 28 1 36 0; +#X connect 29 0 34 1; +#X connect 30 0 26 0; +#X connect 31 0 26 0; +#X connect 32 0 27 0; +#X connect 33 0 27 1; +#X connect 33 0 35 0; +#X connect 34 0 39 0; +#X connect 35 0 34 0; +#X connect 36 0 31 0; +#X connect 37 0 30 0; +#X connect 37 0 38 0; +#X connect 39 0 37 0; -- cgit v1.2.1