10.6

Table Of Contents
306Logic Pro Instruments
These control signals are then sent to the synthesis filter bank—where they control the
levels of the corresponding synthesis filter bands. This is done with voltage-controlled
amplifiers (VCAs) in analog vocoders. Volume changes to the bands in the analysis filter
bank are imposed on the matching bands in the synthesis filter bank. These filter level
changes are heard as a synthetic reproduction of the original input signal—or a mix of the
two filter bank signals.
The more bands a vocoder offers, the more precisely the original sound character is
reproduced by the synthesis filter bank. EVOC20 PolySynth provides up to 20 bands per
bank. See Logic Pro EVOC 20 block diagram for a detailed image of the EVOC 20 PolySynth
signal path.
Logic Pro EVOC20 PolySynth interface
The EVOC20 PolySynth interface is divided into six main parameter sections.
Sidechain Analysis parameters: Determine how the input signal is analyzed and used by
the EVOC20 PolySynth. See Logic Pro EVOC20 PolySynth analysis controls.
U/V Detection parameters: Detect the unvoiced portions of the sound in the analysis
signal, improving speech intelligibility. See Logic Pro EVOC20 PolySynth (U/V)
detection.