hsboscil
Prev | Orchestra Opcodes and Operators | Next

## hsboscil

hsboscil — An oscillator which takes tonality and brightness as arguments.

## Description

An oscillator which takes tonality and brightness as arguments, relative to a base frequency.

## Syntax

    ares hsboscil kamp, ktone, kbrite, ibasfreq, iwfn, ioctfn \
                   [, ioctcnt] [, iphs]

## Initialization

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.

## Performance

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.

## Examples

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

Example 409. Example of the hsboscil opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

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

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

    instr 1 ; produces Risset's glissando.

      kamp = .4
      kbrite = 0.3
      ibasfreq = 200
      ioctcnt = 5

      ; Change ktone linearly from 0 to 1,
      ; over the period defined by p3.
      ktone line 0, p3, 1

    asig hsboscil kamp, ktone, kbrite, ibasfreq, giwave, giblend, ioctcnt
         outs asig, asig

    endin
    </CsInstruments>
    <CsScore>

    i 1 0 10
    e
    </CsScore>
    </CsoundSynthesizer>

Here is an example of the hsboscil opcode in a MIDI instrument. It uses the file hsboscil_midi.csd.

Example 410. Example of the hsboscil opcode in a MIDI instrument.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

    <CsoundSynthesizer>
    <CsOptions>
    ; Select audio/midi flags here according to platform
    ; Audio out
    -odac   -M0 ;;;realtime audio out and realtime MIDI in
    ;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
    ; -o hsboscil_midi.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

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

    instr 1

    ibase = cpsoct(6)
    ioctcnt = 5

    ; all octaves sound alike.
      itona octmidi
      ; velocity is mapped to brightness
      ibrite ampmidi 4

    ; Map an exponential envelope for the amplitude.
    kenv expon .8, 1, .01
    asig hsboscil kenv, itona, ibrite, ibase, giwave, giblend, ioctcnt
         outs asig, asig

    endin
    </CsInstruments>
    <CsScore>

    i 1 0 30 ; play for 30 seconds
    e
    </CsScore>
    </CsoundSynthesizer>

## Credits

Author: Peter Neubäcker
Munich, Germany
August, 1999

New in Csound version 3.58

Prev | Up | Next
hrtfstat | Home | hvs1