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.input.m_return) passes through a quadraphonic All-Pass Filter (m_preFeedbackFilter); the filtered return is then scaled by the feedback amount and summed with the diffused input 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.