Delta Sound Labs Fold
Delta Sound Labs


Regular price R 1,020.00 R 0.00 Unit price per

FOLD - Distortion Synthesis Plug-in

Fold is a distortion synthesis audio effect plug-in that only the engineers at Delta Sound Labs could dream up. Calling on their background in modular hardware design, the team has found a novel approach to creating warmth and distortion in software. By using an assortment of modules in an in-series FX chain, Fold imbues input signals with harmonically rich overtones and, if pushed to the extremes, completely transforms them with a unique form of distortion.

Patch Update 2023 - Change Log (1.1 -> 1.2.)

  • macOS 12/13 build. (Universal build that supports both intel and silicon based machines).
  • Windows 10/11 build.
  • New tape delay module with feedback control and a dedicated LFO.
  • New mono and stereo optimization.
  • New presets. 

Patch Update 2021 - Change Log (1.0 -> 1.1.)

  • On/off buttons for Drive, Fold, Crush and Low Pass filter sections
  • Local mix sliders for Drive, Fold, Crush and Low Pass filter sections
  • Drive/Fold Link button to allow concurrent use of both parameters with one slider
  • FX is now a true Dry/Wet control
  • Envelope follower to control FX amount relative to the peak amplitude of the audio input
  • Hard sync/phase lock for LFO sections
  • Visual feedback for LFO rate
  • Oversampling factor UI
  • New output volume graphical UI slider
  • Stereo spread feature for use with true stereo inputs

At the heart of Fold is its wavefolding engine. First pioneered by synth legend Don Buchla, wavefolding is the act of folding a wave back on itself after reaching a given threshold. While this naturally produces distortion and harmonics, Fold also ships with a bit crusher module to further smash the input signal. Fold's combination of oversampling, distortion, and wavefolding results in tones that are timbrally rich on one hand, and over-the-top destroyed on the other, even with simple periodic input signals.

To tame the sound, Fold comes with an analog emulation of a resonant low-pass filter that offers more control over any unhinged results. Each parameter is also syncable to its own LFO, each of which has an amount slider and may be synced to a host tempo within a DAW for more creative sound design and mixing effects. Fold also ships with a number of professionally designed presets that showcase the versatility of its engine.


  • Hard and Soft Clip Distortion Morphing
  • Wavefolding
  • Bit Crushing
  • Analog Low and High Pass Filter Emulations
  • Four Syncable LFOs with Mappable Phase Reset Buttons
  • Local Mix Sliders on Each Module
  • Three LFO Waveform Types
  • Mono and Stereo Processing
  • Switchable Oversampling
  • Factory and User Presets

The Modules and Effects:

HP Filter

This is a TPT styled high-pass filter with resonance control underneath the frequency knob. It's great for creating filter sweeps on the front end using automation lanes in a DAW.


Drive is an amplitude dependent distortion module. You can crossfade between soft and hard clip distortion using the horizontal slider underneath the drive knob.


Wavefolding is a type of distortion synthesis that occurs when the amplitude of an audio input exceeds a defined threshold. The peaks that exceed the defined threshold are inverted into a series of amplitude folds producing rich timbres and textures. This kind of distortion synthesis really shines when used on simple sounds like sinusoids or standing waves, even single guitar notes. Use the oversampling menu in the toolbar view to choose x1, 2, 4, 8, 16 oversampling. Higher oversampling values incur a greater CPU overhead but mitigate any unwanted aliasing caused by the Fold module.


Crush allows you to quantize your incoming signal to emulate a classic bit crushing effect. Both depth and rate are tied to one single knob and scaled in such a way to leverage this kind of distortion synthesis as best as possible. Listen to the difference when you change the Oversampling factor!

LP Filter

This low-pass filter is an analog emulation of a resonant low-pass filter. There is a resonance control slider underneath the filter frequency cutoff knob in a similar fashion to the high-pass filter on the front end of the signal chain. This filter helps tame and sculpt any unwieldy distorted textures.


Each module has its own dedicated Low Frequency Oscillator (LFO). Each LFO can be turned on by clicking the small button located in the top-left corner and has its own dedicated amount slider located next to the LFO Speed slider. You can choose from sine, square and saw waveform types.

By clicking the quarter note button, Sync mode is activated and locks the phase to the tick reported by the DAW or host.

FX/Envelope Follower

This is a Dry/Wet control that regulates the proportion of processed to unprocessed sound. Adjustments to the FX knob do not affect signal processing, as this is done exclusively by the other modules. The envelope-shaped button underneath the knob will override the FX knob and the amount of effect applied will be relative to the peak amplitude of the incoming audio input.

Toolbar View

Use the preset combo box to select any of our factory presets or make and recall your own presets. You can use the nudge buttons (left and right) to quickly audition presets. The Oversampling drop down menu contains options for x1, x2, x4, x8, and x16 oversampling factors.

Creative Strategies with Fold

Fold yields extremely interesting results with low frequencies—try folding your kick drum, any bass register instruments, or simply a sine wave from your synth! Fold can also be used to add high-frequency energy to a synth lead line. This works well in combination with Fold's FX Amount parameter, allowing you to dial in the exact amount of energy you want. Distortion has long been essential to guitar players—Fold's unique combination of distortion and wavefolding on electric guitars is worth a lengthy exploration. Try with chords or even bass lines on lower registers.

System Requirements



  • Recommended: macOS 12.2 (Monterey)
  • Minimum: macOS 10.13 (High Sierra)


  • Recommended: Windows 11
  • Minimum: Windows 10