iscl (optional, default=0) -- coded scaling factor for resonators. A value of 1 signifies a peak response factor of 1, i.e. all frequencies other than kcf are attenuated in accordance with the (normalized) response curve. A value of 2 raises the response factor so that its overall RMS value equals 1. (This intended equalization of input and output power assumes all frequencies are physically present; hence it is most applicable to white noise.) A zero value signifies no scaling of the signal, leaving that to some later adjustment (see balance). The default value is 0.
iskip (optional, default=0) -- initial disposition of internal data space. Since filtering incorporates a feedback loop of previous output, the initial status of the storage space used is significant. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.
ar -- the output signal at audio rate.
asig -- the input signal at audio rate.
kcf -- the center frequency of the filter, or frequency position of the peak response.
kbw -- bandwidth of the filter (the Hz difference between the upper and lower half-power points).
reson is a second-order filter in which kcf controls the center frequency, or frequency position of the peak response, and kbw controls its bandwidth (the frequency difference between the upper and lower half-power points).
Here is an example of the reson opcode. It uses the files reson.orc and reson.sco.
Example 1. Example of the reson opcode.
/* reson.orc */
/* Written by Kevin Conder */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; Instrument #1.
instr 1
; Generate a sine waveform.
asine buzz 15000, 440, 3, 1
; Vary the cut-off frequency from 220 to 1280.
kcf line 220, p3, 1320
kbw init 20
; Run the sine through a resonant filter.
ares reson asine, kcf, kbw
; Give the filtered signal the same amplitude
; as the original signal.
a1 balance ares, asine
out a1
endin
/* reson.orc */
/* reson.sco */
/* Written by Kevin Conder */
; Table #1, an ordinary sine wave.
f 1 0 16384 10 1
; Play Instrument #1 for 4 seconds.
i 1 0 4
e
/* reson.sco */