[PD] allpass filters?

Michael Berkowski berk0081 at tc.umn.edu
Wed Mar 9 15:08:10 CET 2005


Hi David,

The cyclone library has an allpass~, but I find it easier just to use the 
attached abstraction.  It's easily adaptible to single and double-nested 
allpass networks as well.

It takes two arguments:  1) delay time in ms 2) feedback as float 0-1

I'm developing a sort of reverberation toolkit of unit reverberator 
abstractions and "classic" reverb implementations, which will include these.

Best,
Michael Berkowski
michael_at_berkowski_dot_net
http://www.berkowski.net/


filename: mb.allpass~.pd

#N canvas 445 296 617 251 10;
#X obj 211 -4 inlet~;
#X text 258 -4 Main signal inlet;
#X obj 369 43 f \$1;
#X obj 369 -4 inlet;
#X text 409 -7 Delay time;
#X text 409 6 NOT VARIABLE;
#X obj 3 201 outlet~;
#X obj 515 -4 inlet;
#X obj 515 43 f \$2;
#X text 94 186 First argument is delay time \,;
#X obj 225 16 s~ \$0-allpass_sig_in;
#X obj 236 85 r~ \$0-allpass_sig_in;
#X obj 369 62 s \$0-allpass_deltime;
#X obj 3 1 r \$0-allpass_deltime;
#X obj 236 118 +~;
#X obj 211 62 *~;
#X text 553 -3 Feedback;
#X obj 102 62 *~;
#X text 235 63 Feedforward Path;
#X text 125 63 Feedback Path;
#X text 93 157 This is a standard Allpass delay;
#X text 95 168 with a feedback and feedforward path.;
#X text 183 219 12.March.2004;
#X obj 236 137 delwrite~ \$0-mb_allpass~ 150;
#X obj 3 20 delread~ \$0-mb_allpass~ 72;
#X obj 435 21 loadbang;
#X obj 3 181 +~;
#X obj 16 162 *~ -1;
#X text 94 200 Second argument is Feedback gain (0-1).;
#X obj 515 62 s \$0-gain;
#X obj 115 41 r \$0-gain;
#X obj 16 60 pow 2;
#X obj 16 118 -;
#X msg 16 99 1;
#X obj 16 80 t b f;
#X obj 3 138 *~;
#X connect 0 0 10 0;
#X connect 0 0 15 0;
#X connect 2 0 12 0;
#X connect 3 0 2 0;
#X connect 7 0 8 0;
#X connect 8 0 29 0;
#X connect 11 0 14 0;
#X connect 13 0 24 0;
#X connect 14 0 23 0;
#X connect 15 0 27 0;
#X connect 17 0 14 1;
#X connect 24 0 17 0;
#X connect 24 0 35 0;
#X connect 25 0 2 0;
#X connect 25 0 8 0;
#X connect 26 0 6 0;
#X connect 27 0 26 1;
#X connect 30 0 15 1;
#X connect 30 0 17 1;
#X connect 30 0 31 0;
#X connect 31 0 34 0;
#X connect 32 0 35 1;
#X connect 33 0 32 0;
#X connect 34 0 33 0;
#X connect 34 1 32 1;
#X connect 35 0 26 0;

----------------
>Message: 8
>From: "david golightly" <davigoli at hotmail.com>
>To: pd-list at iem.at
>Subject: [PD] allpass filters?
>Date: Tue, 08 Mar 2005 21:00:09 -0500
>
>Hello again List,
>
>I'm stumped here - does PD have any built-in allpass filter?  If not, is
>there an external out there that I should know about?  Thanks!
>
>David





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