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

## Examples

The result can be viewed in a graphical audio editor program like audacity. audacity is available for Linux, Windows, and the MacOS and may be downloaded from http://audacity.sourceforge.net.

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

Example 209. 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
    -odac     ;;;RT audio out
    ;-iadc    ;;;uncomment -iadc if RT audio input is needed too
    ; For Non-realtime ouput leave only the line below:
    ;-o dcblock.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

    sr = 44100
    ksmps = 32
    nchnls = 2

    instr 1	;add DC to "drumsMlp.wav"

    asig soundin "drumsMlp.wav"
    asig = asig+5000	;adds DC of 5000
         outs asig, asig
    endin

    instr 2	;dcblock audio

    asig soundin "drumsMlp.wav"
    asig = asig+5000	;adds DC
    adc  dcblock asig	;remove DC again
         outs adc, adc

    endin

    </CsInstruments>
    <CsScore>

    i 1 0 2
    i 2 2 2
    e

    </CsScore>
    </CsoundSynthesizer>

## See also

Specialized Filters: High pass filters

## Credits

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

New in Csound version 3.49

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

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