lowres — Another resonant lowpass filter.


lowres is a resonant lowpass filter.


ares lowres asig, kcutoff, kresonance [, iskip]


iskip -- initial disposition of internal data space. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.


asig -- input signal

kcutoff -- filter cutoff frequency point

kresonance -- resonance amount

lowres is a resonant lowpass filter derived from a Hans Mikelson orchestra. This implementation is much faster than implementing it in Csound language, and it allows kr lower than sr. kcutoff is not in Hz and kresonance is not in dB, so experiment for the finding best results.


Here is an example of the lowres opcode. It uses the file lowres.csd and beats.wav.

Example 240. Example of the lowres opcode.

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

; Select audio/midi flags here according to platform
; Audio out   Audio in    No messages
-odac           -iadc     -d     ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o lowres.wav -W ;;; for file output any platform

; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1

; Instrument #1.
instr 1
  ; Use a nice sawtooth waveform.
  asig vco 5000, 440, 1

  ; Vary the cutoff frequency from 30 to 300 Hz.
  kcutoff line 30, p3, 300
  kresonance = 10

  ; Apply the filter.
  a1 lowres asig, kcutoff, kresonance 

  out a1


; Table #1, a sine wave for the vco opcode.
f 1 0 16384 10 1

; Play Instrument #1 for two seconds.
i 1 0 2


See Also



Author: Gabriel Maldonado (adapted by John ffitch)

Example written by Kevin Conder.

New in Csound version 3.49