rezzy — A resonant low-pass filter.


A resonant low-pass filter.


ares rezzy asig, xfco, xres [, imode, iskip]


imode (optional, default=0) -- high-pass or low-pass mode. If zero, rezzy is low-pass. If not zero, rezzy is high-pass. Default value is 0. (New in Csound version 3.50)

iskip (optional, default=0) -- if non zero skip the initialisation of the filter. (New in Csound version 4.23f13 and 5.0)


asig -- input signal

xfco -- filter cut-off frequency in Hz. As of version 3.50, may i-,k-, or a-rate.

xres -- amount of resonance. Values of 1 to 100 are typical. Resonance should be one or greater. As of version 3.50, may a-rate, i-rate, or k-rate.

rezzy is a resonant low-pass filter created empirically by Hans Mikelson.


Here is an example of the rezzy opcode. It uses the file rezzy.csd.

Example 742. Example of the rezzy opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

; Select audio/midi flags here according to platform
-odac   ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o rezzy.wav -W ;;; for file output any platform

sr = 44100 
ksmps = 32 
0dbfs  = 1 
nchnls = 2

instr 1

asaw vco2 .3, 110	;sawtooth
kcf  line 1760, p3, 220	;vary cut-off frequency from 220 to 1280 Hz
kres = p4		;vary resonance too		
ares rezzy asaw, kcf, kres
asig balance ares, asaw
     outs asig, asig


i 1 0 4 10
i 1 + 4 30
i 1 + 4 120	;lots of resonance

See Also

biquad, moogvcf


Author: Hans Mikelson
October 1998

New in Csound version 3.49