Tone, from Qu-Bit Electronix, is four voltage controlled filters behind one panel. Each filter has its own audio input and CV control, with both Bandpass and Lowpass outputs. Each filter utilizes OTA topology to provide the warm, buttery filter tone with a characteristic -24dB filter slope, similar to Moog style filters. Each filter's resonance control can be increased up to self oscillation, providing four clean sine tones that can be tracked musically over four octaves.
Quad voltage controlled filter
24 dB slope
Simultaneous low pass and band pass outputs
Self oscillation with v/oct tracking across four octaves
This second part of our series on physical modeling synthesis with eurorack modular synthesizers covers modal synthesis. Modal synthesis utilizes many resonant bandpass filters as a resonator which can then be excited by many different types of impulses or sounds. Since most modal synthesis models use dozens or hundreds of bandpass filters digital implementations are more practical, but we put this together with analog bandpass filters to see how it would work.