Sound: Filter (pre-emphasis)...

A command to filter each selected Sound object. The resulting Sound object has a higher spectral slope.

The reverse of Sound: Filter (de-emphasis)....

Setting

From frequency (Hz)
the frequency F above which the spectral slope will increase by 6 dB/octave.

Algorithm

The pre-emphasis factor α is computed as

α = exp (-2 π F Δt)

where Δt is the sampling period of the sound. The new sound y is then computed as:

yi = xi - α xi-1

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© ppgb, March 9, 2003