10.6

133Logic Pro Effects
EVOC 20 Filterbank
Logic Pro EVOC 20 Filterbank overview
EVOC 20 Filterbank consists of two formant filter banks. The input signal passes through
the two filter banks in parallel. Each bank features level faders for up to 20 frequency
bands, allowing independent level control of each band. Setting a level fader to its
minimum value completely suppresses the formants in that band. You can control the
position of the filter bands with the Formant Shift parameter. You can also crossfade
between the two filter banks.
The EVOC 20 Filterbank interface is divided into three main sections: the Formant Filter
parameters section in the center of the window, the Modulation parameters section at
the bottom, and the Output parameters section along the right side.
• Formant Filter parameters: Control the frequency bands in the two filter banks—the
upper, blue, filter bank A and the lower, green, filter bank B. See Logic Pro
EVOC 20
Filterbank Formant Filter.
• Modulation parameters: Control how Formant Filter parameters are modulated. See
Logic Pro
EVOC 20 Filterbank modulation.
• Output parameters: Control the overall output level and panning of the EVOC 20
Filterbank. See Logic Pro EVOC 20 Filterbank output controls.
A short introduction to formants
A formant is a peak in the frequency spectrum of a sound. In the context of human
voices, formants are the key component that enables humans to distinguish between
different vowel sounds, based purely on the frequency of these sounds. Formants in
human speech and singing are produced by the vocal tract, with most vowel sounds
containing four or more formants.