Intellijel Atlantis - Manual (Page 39)

The Voltage Controlled Filter section consists of a combination of 3 types of filter (Low-Pass, Band-Pass and High-Pass) switchable to 2 different slopes (12 and 24
dB). So you dispose of 9 filtering methods, plus BOOST for the LP mode. Each mode can self-oscillate and then produces a clean sine-wave that can be controlled
at 1V/OCT (from the Primary VCO).
The sum out of the MIXer section is normaled to the VCF input, you can break this normal with patching a signal at the EXTernal INput and by this way use the VCF
section as a totally independent filter.
Overview
VCF section - 01
set VCF slope
VCF out to VCA section set LP BOOST
modulate cutoff FREQuency
VCF out
set VCF type
adjust RESonance
External INput
signal