vlowres — A bank of filters in which the cutoff frequency can be separated under user control.


A bank of filters in which the cutoff frequency can be separated under user control


ares vlowres asig, kfco, kres, iord, ksep


iord -- total number of filters (1 to 10)


asig -- input signal

kfco -- frequency cutoff (not in Hz)

ksep -- frequency cutoff separation for each filter

vlowres (variable resonant lowpass filter) allows a variable response curve in resonant filters. It can be thought of as a bank of lowpass resonant filters, each with the same resonance, serially connected. The frequency cutoff of each filter can vary with the kcfo and ksep parameters.


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

Example 496. Example of the vlowres 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 vlowres.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 32000, 220, 1

  ; Vary the cutoff frequency from 30 to 300 Hz.
  kfco line 30, p3, 300
  kres = 25
  iord = 2
  ksep = 20

  ; Apply the filters.
  avlr vlowres asig, kfco, kres, iord, ksep

  ; It gets loud, so clip the output amplitude to 30,000.
  a1 clip avlr, 1, 30000
  out a1


; Table #1, a sine wave.
f 1 0 16384 10 1

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



Author: Gabriel Maldonado

Example written by Kevin Conder.

New in Csound version 3.49