Frap Tools: Three LFO Tricks to Elevate Your Modular Patches

The first technique transforms a basic LFO into a one-shot, pitch-shifting envelope. Giovanni switches LFO 1 into envelope mode, making it unipolar and ensuring the output only rises above zero. He then sets it to a square wave so it toggles between just two voltage levels. Routing this LFO to oscillator pitch, he demonstrates that the modulation depth determines the pitch jump: a value of 50 sends the pitch up two octaves, while 25 yields a one-octave hop.

Fine-tuning the rate time creates a quick attack that pushes the pitch higher before it drops back, effectively mimicking a classic monosynth pitch envelope. To keep things musically lively, he tweaks the tuning and adds delay, resulting in a snappy, dynamic patch that’s as immediate as it is effective. This is a textbook example of using modular tools for more than their names suggest—an LFO as an envelope, doing melodic work.

Next, the focus shifts to cross-modulation, using two LFOs to control one another for layered complexity. The patch is reset—delay off, key tracking added to the filter for extra brightness. The first LFO stays unipolar but is taken out of envelope mode and set to square wave, which avoids unwanted audio artifacts. The LFO can run in mono, modulating all notes in unison, or be tempo-synced for rhythmic movement—Giovanni demonstrates both eighth and quarter note divisions for the LFO rate.

To nest modulations, LFO 2 is also tempo-synced but set slower, and it modulates the rate of LFO 1. Both LFOs are in square mode, so the result is a stepped, machine-like modulation that remains musical thanks to sync. Delay is synced as well for cohesion, and the attack and release are smoothed for a less abrupt modulation shape. The outcome is a patch with evolving, clocked modulation layers—a modular answer to classic step-sequencing, but with all the flexibility of voltage control.

The final trick dives into polyphonic LFO operation for those with multi-voice setups. Resonance is increased on the filter, and LFO 1 is set to polyphonic mode and a solid wave. Each voice now receives its own LFO instance, modulating cutoff with a snappy contour and moderate rate for movement. By applying an unused envelope to modulate the LFO rate, Giovanni creates a sweep: the LFO starts out fast and slows according to the envelope, giving each note a unique, organic motion.

Transposing everything down and closing the filter’s timbre, he highlights the effect: in polymode, the LFOs create a bouncing, ping-pong feel between voices. Monophonic LFOs are stiffer, less lively. As a final flourish, aftertouch is patched to bring the LFO rate back up, allowing expressive, real-time modulation. This technique demonstrates how voice-specific LFOs can animate a patch far beyond what global modulation achieves.