STKVoicForm — STKVoicForm is a four formant 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:

STKVoicForm is a four formant synthesis instrument. This instrument contains an excitation singing wavetable (looping wave with random and periodic vibrato, smoothing on frequency, etc.), excitation noise, and four sweepable complex resonances. Measured formant data is included, and enough data is there to support either parallel or cascade synthesis. In the floating point case cascade synthesis is the most natural so that us what you will find here.


asignal STKVoicForm ifrequency, iamplitude, [kmix, kv1[, ksel, kv2[, klfo, kv3[, klfodepth, kv4[, kloud, kv5]]]]]


ifrequency -- Frequency of note played, in Hertz.

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


kmix -- controller 2, voiced/unvoiced mix. Value range of kv1 is 0-127.

ksel -- controller 4, vowel/phoneme selection. 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.

kloud -- controller 128, loudness (spectral tilt). Value range of kv5 is 0-127.

[Note] Note

The code for this opcode is taken directly from the VoicForm 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 STKVoicForm opcode. It uses the file STKVoicForm.csd.

Example 1057. Example of the STKVoicForm 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 STKVoicForm.wav -W ;;; for file output any platform

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

instr 1

ifrq	=	p4
kv2	line	p5, p3, p6				;Vowel/Phoneme Selection

asig	STKVoicForm cpspch(p4), 1, 2, 1, 4, kv2, 128, 100, 1, 10, 11, 100
asig	=	asig * .5				;too loud
	outs asig, asig


i 1 0 5  7.00 100 0
i 1 + 10 7.00 1  50

See also

STK Opcodes


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

New in Csound version 5.11