Quad resonance filter array and equalizer

The RES-4 combines four highly sensitive, parallel bandpass filters with global master controls to shape intricate acoustic resonances, formant vocalisms, and physical modeling percussion.

This precise multi-band resonator operates as an advanced spectral sculptor, building on a heavily expanded equalizer topology. Each of its four identical filter sections features dedicated manual dials and CV inputs for frequency, bandwidth, and amplitude. Instead of conventional synthetic filtering, the module concentrates on micro-tonal adjustments and acoustic emulation across a wide 16Hz to 16kHz frequency range.

The bandwidth controls dictate the resonance and decay behavior of each band. While the circuit intentionally stops short of full self-oscillation, feeding sharp triggers or noise bursts into the audio input coaxes organic, woody, and metallic plucks out of the filters. For complex performances, the master section unifies the array, allowing you to transpose intricate multi-band clusters or execute massive global sweeps with a single control voltage source.

In use, the module excels at turning static waveforms into shifting, vowel-like formants or heavy, tuned percussion. The dual audio outputs offer distinct spatial signatures: the bandpass output sums all channels in phase, while the notch output phase-inverts channels two and four. Panning these two outputs left and right creates a wide, immersive psychoacoustic stereo field. A mechanical bypass switch lets you instantly A/B your dry and processed signals during live sets. Note that the power connector follows Cwejman standard protocol, where the red stripe on the ribbon cable indicates the positive 12V rail.