STKFMVoices — STKFMVoices is a singing FM synthesis instrument.


Plugin opcode in stkopd. This opcode is part of the plugin repository and has to be installed separately. The plugin repository can be found here:

STKFMVoices is a singing FM synthesis instrument. It has 3 carriers and a common modulator, also referred to as algorithm 6 of the TX81Z.


asignal STKFMVoices ifrequency, iamplitude, [kvowel, kv1[, kspec, kv2[, klfo, kv3[, klfodepth, kv4[, kadsr, kv5]]]]]


ifrequency -- Frequency of note played, in Hertz.

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


kvowel -- controller 2, vowel. Value range of kv1 is 0-127.

kspec -- controller 4, spectral tilt. Value range of kv2 is 0-127.

klfo -- controller 11, speed of low-frequency oscillator. Value range of kv3 is 0-127.

klfodepth -- controller 1, depth of low-frequency oscillator. Value range of kv4 is 0-127.

kadsr -- controller 128, ADSR 2 and 4 Target. Value range of kv5 is 0-127.

[Note] Note

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

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). Both the controller numbers and the controller values are krate variables. However, during a performance, normally the controller numbers stay fixed while the corresponding controller values may change at any time. The order of the controller pair is arbitrary, as long as they are after iamplitude. Also, it is not needed that all controller pairs are used.


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

Example 1042. Example of the STKFMVoices opcode.

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

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

instr 1

ifrq	=	p4
kv1	line	p5, p3, p6					;vowel
kv2	line	p7, p3, p8					;specral tilt

asig	STKFMVoices cpspch(ifrq), 1, 2, kv1, 4, kv2, 11, 10, 1, 10, 128, 50
asig	=	asig * 4					;amplify
	outs asig, asig


i 1 0 5 5.00 10 120 0 0 
i 1 + 2 8.00 80 82 127 0

See also

STK Opcodes


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

New in Csound version 5.11