Introduction
FORMANTIC is a voltage controlled analog formant filter that combines two resonant 12dB bandpass
filters (BP) with one resonant 24dB lowpass filter (LP). Each filter has its own set of controls for
resonance and cutoff frequency. All three filters can be driven into self-oscillation.
There are two inputs. IN A routes the signal through all filters while IN B is routed through the LP filter
only. The Path switch lets you process your audio signal in series or parallel. The output signal is split
into Main Out (BP + LP) and BP Out which in turn opens up for further processing like quasi-stereo
effects etc. A unique feature of the Formantic filter is the joystick which enables intuitive interaction of
both BP filters, while the large Master Cutoff knob lets you sweep all filters simultaneously.
FORMANTIC is a free interpretation of the filter topology found in Synton's rare Syrinx synthesizer, which
was manufactured in the Netherlands in the early 1980s. However, this is not a clone; rather, our circuit is
an original Noise Lab design, engineered with numerous novel ideas that we believe set this filter apart in
many ways.
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① IN A
Input A is connected to the Path switch (see below) and routes the
signal through both BP and LP filters. Signal out via BP OUT and MAIN
OUT. The input signal is expected to be 10Vpp.
② IN B
This input is only routed via the 24dB LP filter and to the MAIN OUT.
The input signal is expected to be 10Vpp.
③ Path Switch
The PATH switch lets you process your sound through the filters in
series or parallel.
If the switch is set to the down position, the signal is routed through the
BP filters first, followed by the LP filter. In up position, the signal is split
and runs in parallel through the BP and LP filters. This has a major
impact on the sound and offers a lot of interesting ways to shape your
sound. Please note, this only applies to audio via Input A.
