Tetrad

Tetrad is a hybrid instrument from Physical Audio that blends physical modelling with granular synthesis for immersive, sculptural sound design. Four oscillators with frequency modulation feed a quad amplitude modulation processor, then a granulator, and finally four physically modelled plate resonators. A 4×4 matrix mixer lets you route and blend signals creatively, while a sidechain audio option bypasses the oscillators so any external sound can be processed. The quad granulator splits audio into grains with control over window shape, size, pitch, and feedback. Four modelled plates add preamp drive and sound stage design, with three filter sections offering lowpass, band, or highpass. A full modulation matrix includes eight LFOs, MIDI and MPE sources, plus envelope followers from the AM and granulator levels. With MPE and MTS-ESP microtuning support, Tetrad suits producers exploring experimental textures, evolving drones, and cinematic soundscapes.