dcblock

dcblock — A DC blocking filter.

Description

Implements the DC blocking filter


Y[i] = X[i] - X[i-1] + (igain * Y[i-1])
      

Based on work by Perry Cook.

Syntax

ares dcblock ain [, igain]

Initialization

igain -- the gain of the filter, which defaults to 0.99

Performance

ain -- audio signal input

[Note] Note

The new dcblock2 opcode is an improved method of removing DC from an audio signal.

Examples

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

Example 112. Example of the dcblock 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
; Audio out   Audio in    No messages
-odac           -iadc     -d     ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o dcblock.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

; Instrument #1 -- normal audio signal.
instr 1
  asig soundin "beats.wav"
  out asig
endin

; Instrument #2 -- dcblock-ed audio signal.
instr 2
  asig soundin "beats.wav"

  igain = 0.75
  a1 dcblock asig, igain

  out a1
endin


</CsInstruments>
<CsScore>

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


</CsScore>
</CsoundSynthesizer>


See also

dcblock2

Credits

Author: John ffitch
University of Bath, Codemist Ltd.
Bath, UK

Example written by Kevin Conder.

New in Csound version 3.49

February 2003: Thanks to a note from Anders Andersson, corrected the formula.