Fold is a distortion synthesis audio effect plugin developed by Delta Sound Labs, inspired by modular hardware design. It introduces a fresh method to generate warmth and distortion by chaining various modules in series, enriching input signals with harmonically complex overtones. When driven harder, Fold drastically reshapes the sound with a distinctive distortion character that stands out from typical effects.

Central to Fold's sound is its wavefolding engine, a technique originally popularized by synth pioneer Don Buchla. This process folds a waveform back on itself once it crosses a threshold, producing unique distortion and harmonic content. Additionally, Fold includes a bit crusher module that further degrades the signal for more aggressive effects. The combination of oversampling, wavefolding, and distortion allows Fold to deliver sounds ranging from subtly warm to heavily saturated, even with simple input tones.

To manage the intensity of its effects, Fold features an analog-style resonant low-pass filter along with several syncable LFOs that can be tempo-synced within a DAW. This setup offers extensive control for shaping and modulating the sound dynamically. Fold comes with a collection of expertly crafted presets that highlight its capability across various applications, from thickening bass and kick drums to adding brightness to synth leads and transforming electric guitars with rich texture and grit.