The Alternative Csound Reference Manual
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# specfilt

specfilt -- Filters each channel of an input spectrum.

## Description

Filters each channel of an input spectrum.

## Syntax

wsig specfilt wsigin, ifhtim

## Initialization

ifhtim -- half-time constant.

## Performance

wsigin -- the input spectrum.

Filters each channel of an input spectrum. At each new frame of wsigin, each magnitude value is injected into a 1st-order lowpass recursive filter, whose half-time constant has been initially set by sampling the ftable ifhtim across the (logarithmic) frequency space of the input spectrum. This unit effectively applies a persistence factor to the data occurring in each spectral channel, and is useful for simulating the energy integration that occurs during auditory perception. It may also be used as a time-attenuated running histogram of the spectral distribution.

## Examples

      wsig2    specdiff         wsig1               ; sense onsets
      wsig3    specfilt         wsig2, 2            ; absorb slowly
               specdisp         wsig2, .1           ; & display both spectra
               specdisp         wsig3, .1

## See Also

specaddm, specdiff, spechist, specscal

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