Frap Tools: Cross-FM, Fake Polyphony and Modular Mute Sorcery – A Performance Dissected

The Brenso oscillator takes centre stage as the main melodic voice, with both of its oscillators tuned to the same frequency and patched for cross-FM. This setup yields a sound that’s intentionally abrasive and unstable, yet—thanks to the shared tuning—retains a solid pitch centre. Gennari emphasises that this approach provides a rich, shifting timbre without sacrificing melodic clarity, a balance that’s often elusive in more chaotic FM patches.

Signal flow is key here: the triangle wave is shaped, compared, and pulsed before hitting the low pass gate. Modulation of the FM deviation is handled externally, allowing for dynamic control over the amount of cross-modulation in real time. The result is a voice that can morph from smooth to serrated at the twist of a knob or the nudge of a sequencer lane, all while staying musically grounded.

To conjure the illusion of polyphonic strings, Gennari routes the Brenso’s output through the Verbos Multi Delay Processor. By exploiting the delay’s mix outputs and stereo panning, he creates a dense, overlapping field of notes—effectively faking polyphony from a single monophonic source. The resulting texture is both lush and spatial, with note overlaps and pan movement lending the impression of multiple voices bowing in unison.

Further depth comes from subtle modulation: an envelope follower nudges the delay time, while the octaver and feedback loops add harmonic complexity. The envelope, shaped by the green channel of Falistri, controls the VCA for a bowed-string effect, and the QSC mixer provides hands-on control over the dynamics. It’s a clever patching strategy that turns a single oscillator into a convincing ensemble.

The QSC Quad Stereo Channel mixer isn’t just a utility here—it’s a performance instrument in its own right. Gennari demonstrates how its mute buttons, combined with sequencer-based gate muting, allow for nuanced control over when effects and voices enter or exit the mix. This hands-on approach enables quick, expressive changes, whether it’s bringing in a reverb tail at the climax or dropping out a voice for dramatic effect.

The ergonomic placement of the mute buttons is highlighted as a practical advantage, making it easy to trigger multiple mutes simultaneously. This tactile control, paired with the routing flexibility of the QSC, supports a workflow where mixing and modulation are as performative as the sound sources themselves.