A command to change the spectral slope of every selected Sound object.
The reverse of Sound: Pre-emphasize (in-line).... For an example, see Source-filter synthesis.
This is the in-line version of Sound: Filter (de-emphasis)..., i.e., it does not create a new Sound object but modifies an existing object.
The de-emphasis factor α is computed as
|α = exp (-2 π F Δt)|
where Δt is the sampling period of the sound. Every sample xi of the sound, except x1, is then changed, going up from the second sample:
|xi = xi + α xi-1|
© ppgb, March 9, 2003