STKResonate — STKResonate is a noise driven formant filter.


STKResonate is a noise driven formant filter. This instrument contains a noise source, which excites a biquad resonance filter, with volume controlled by an ADSR.


asignal STKResonate ifrequency, iamplitude, [kc1, kv1[, kc2, kv2[, kc3, kv3[, kc4, kv4[, kc5, kv5]]]]]


ifrequency -- Frequency of note played, in Hertz.

iamplitude -- Amplitude of note played (range 0-1).


kc1, kv1, kc2, kv2, kc3, kv3, kc4, kv4, kc5, kv5, kc6, kv6, kc7, kv7, kc8, kv8 -- Up to 8 optional k-rate controller pairs for the STK opcodes. Each controller pair consists of a controller number (kc) followed by a controller value (kv). The 5 controller numbers and values that work for STKResonate are:

  • kc, kv -- 2, frequency of resonance.

  • kc, kv -- 4, pole radii.

  • kc, kv -- 11, notch frequency.

  • kc, kv -- 1, zero radii.

  • kc, kv -- 128, gain of envelope.

[Note] Note

The code for this opcode is taken directly from the Resonate class in the Synthesis Toolkit in C++ by Perry R. Cook and Gary P. Scavone. More on the STK classes can be found here:


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

Example 753. Example of the STKResonate opcode.

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

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

instr 1 ; frequency of STKResonate has no effect on sound

kpol	=	p4				;pole radii
kfrq	line	100, p3, 0			;resonance freq + notch freq

asig	STKResonate 1, 1, 2, kfrq, 4, kpol, 1, 10, 11, kfrq, 128, 127
asig	=	asig * .7			;too loud
	outs asig, asig


i 1 0 1 0 
i 1 + . >
i 1 + . >
i 1 + . >
i 1 + . 120


Author: Michael Gogins (after Perry Cook)
Irreducible Productions
New York, NY

New in Csound version 5.11