Doepfer A-100(~ 40 MB) - Manual (Page 276)

A-121 VCF 2 System A - 100 doepfer
8
Generating vocal effects
With the patch in Fig. 4 (see next page) vocal effects
can be produced, using two A-121 filters.
A sawtooth at around 100 Hz or less is patched into
two A-121 filters. Set Q to a small or medium level,
and use different mid-frequencies for each of the two
filters.
Modulate the VCO and both filters with a triangle wave
LFO at about 1 Hz, but with the voltage input to one of
the filters inverted by an A-175 inverter. Set the
modulation amount for the VCO (Attenuator CV3) and
for the filter (Attenuator FCV2) to a small or medium
value.
You can control the intensity of the modulation with a
dynamic MIDI controller - aftertouch, mod wheel, etc..
Experiment a little with this patch (see next page). With
careful setting up and tweaking, interesting vocal-like
timbres can be produced.