An oscillator which takes tonality and brightness as arguments, relative to a base frequency.
ibasfreq -- base frequency to which tonality and brighness are relative
iwfn -- function table of the waveform, usually a sine
ioctfn -- function table used for weighting the octaves, usually something like:
f1 0 1024 -19 1 0.5 270 0.5
ioctcnt (optional) -- number of octaves used for brightness blending. Must be in the range 2 to 10. Default is 3.
iphs (optional, default=0) -- initial phase of the oscillator. If iphs = -1, initialization is skipped.
kamp -- amplitude of note
ktone -- cyclic tonality parameter relative to ibasfreq in logarithmic octave, range 0 to 1, values > 1 can be used, and are internally reduced to frac(ktone).
kbrite -- brightness parameter relative to ibasfreq, achieved by weighting ioctcnt octaves. It is scaled in such a way, that a value of 0 corresponds to the orignal value of ibasfreq, 1 corresponds to one octave above ibasfreq, -2 corresponds to two octaves below ibasfreq, etc. kbrite may be fractional.
hsboscil takes tonality and brightness as arguments, relative to a base frequency (ibasfreq). Tonality is a cyclic parameter in the logarithmic octave, brightness is realized by mixing multiple weighted octaves. It is useful when tone space is understood in a concept of polar coordinates.
Making ktone a line, and kbrite a constant, produces Risset's glissando.
Oscillator table iwfn is always read interpolated. Performance time requires about ioctcnt * oscili.
Here is an example of the hsboscil opcode. It uses the files hsboscil.orc and hsboscil.sco.
Example 15-1. Example of the hsboscil opcode.
/* hsboscil.orc */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; synth waveform
giwave ftgen 1, 0, 1024, 10, 1, 1, 1, 1
; blending window
giblend ftgen 2, 0, 1024, -19, 1, 0.5, 270, 0.5
; Instrument #1 - produces Risset's glissando.
instr 1
kamp = 10000
kbrite = 0.5
ibasfreq = 200
ioctcnt = 5
; Change ktone linearly from 0 to 1,
; over the period defined by p3.
ktone line 0, p3, 1
a1 hsboscil kamp, ktone, kbrite, ibasfreq, giwave, giblend, ioctcnt
out a1
endin
/* hsboscil.orc */
/* hsboscil.sco */
; Play Instrument #1 for ten seconds.
i 1 0 10
e
/* hsboscil.sco */
Here is an example of the hsboscil opcode in a MIDI instrument. It uses the files hsboscil_midi.orc and hsboscil_midi.sco.
Example 15-2. Example of the hsboscil opcode in a MIDI instrument.
/* hsboscil_midi.orc */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; synth waveform
giwave ftgen 1, 0, 1024, 10, 1, 1, 1, 1
; blending window
giblend ftgen 2, 0, 1024, -19, 1, 0.5, 270, 0.5
; Instrument #1 - use hsboscil in a MIDI instrument.
instr 1
ibase = cpsoct(6)
ioctcnt = 5
; all octaves sound alike.
itona octmidi
; velocity is mapped to brightness
ibrite ampmidi 3
; Map an exponential envelope for the amplitude.
kenv expon 20000, 1, 100
asig hsboscil kenv, itona, ibrite, ibase, giwave, giblend, ioctcnt
out asig
endin
/* hsboscil_midi.orc */
/* hsboscil_midi.sco */
; Play Instrument #1 for ten minutes
i 1 0 6000
e
/* hsboscil_midi.sco */