3.1 Structure of the filterbank
The module has an analog filter bank consisting of 12 filter bands. The first 11 filter bands are
24db bandpasses (resonance filters) with fixed frequencies and medium resonance, the excep-
tion being channel 12, a 24dB highpass filter that lets through all higher frequencies from around
5Khz.
The center frequencies of the channels are:
90Hz, 150Hz, 240Hz, 350Hz, 500Hz, 700Hz, 1KHz, 1.4KHz, 2KHz, 2.8KHz, 3.9KHz, >5.6KHz
Each filter band has an output volume slider. This allows you to lower these frequencies in the
overall sound or remove them entirely. Up to this point, the filter bank resembles a graphic equa-
lizer. But the filters in the CURVES have other properties that clearly distinguish them from an
equalizer. On the one hand, there are the resonant filters that particularly amplify the range
around the respective center frequencies. On the other hand, the individual frequency bands do
not overlap. Therefore, the timbre is noticeably affected because it adds resonances at key
points in the sound spectrum.
Each channel has a VCA for electronic volume control through the internal sequencer or sepa-
rately through the BAND CV input. With a CV voltage of 0 to +5v the channel can be regulated
separately. The BAND Leds signal the level of the VCA. Each channel has an additional output
for the audio signal, which can be tapped independently at the socket. The channel control has
no influence on the level (in order to be able to process the signal separately, even though it may
have been removed from the mix).
3. FILTERBANK
8
u
v
w
x
BAND LEDs
LED display VCA level of the filter band
BAND SLIDERS
Audio filter band attenuators
BAND AUDIO OUT
Audio individual outputs of all filter bands
BAND CV IN
CV inputs of the VCAs of the filter bands
u
v
w
x
