The Quad Reverb (QuadReverb in private/src/QuadReverb.hpp) is the secondary global effect in the Smart Grid One, providing dense, quadraphonic spatialization.
Unlike the highly experimental Phase Vocoder Quad Delay, the Quad Reverb follows a more traditional algorithmic reverb topology, scaled up to four channels:
QuadParallelAllPassFilter<8>). This rapidly diffuses the initial transients, smearing them into a dense cluster of early reflections. The delay times for these APFs are chosen as prime numbers (e.g., 37, 61, 113…) to minimize metallic ringing.m_preFeedbackFilter) before entering the main delay loop.QuadDelayLine) provides the core reverberant tail. The delay times are modulated by a dedicated QuadLFO to add chorus and prevent resonant build-up.PostFeedbackFilter block consisting of:
m_apf1).QuadOPBaseWidthFilter acting as a damping stage to roll off high and low frequencies).m_apf2).TanhSaturator prevents the feedback loop from blowing up and adds a touch of warmth to the reverb tail.output.Hadamard() in TransformOutput). This mixes the four channels together in an orthogonal fashion, diffusing energy evenly and avoiding simple left/right or front/back swaps. The result is a dynamic, spatially immersive reverberant field with enhanced envelopment and movement. The Quad Delay uses a different approach (RotateLinear with a continuous m_rotate parameter) for its channel mixing.QuadLFO modulates the main delay lines, providing lush, chorused tails.