Granular Synthesis

Granular synthesis operates by segmenting an audio signal into small snippets called grains, which are typically 1–1000 milliseconds in duration. These grains are individually shaped, positioned, and modulated to create rich, evolving textures that are not achievable via traditional synthesis. The controls in the provided interface represent the core parameters that define granular behaviour:

Grain Engine

• Grain Size: Sets the duration of each grain. Longer grains tend toward smoother, more tonal output; shorter grains produce more noisy or percussive textures.
• Grain Rate: Defines how frequently new grains are generated. Higher rates increase density and can result in a more continuous signal.
• Overlap : Indicates that multiple grains are playing simultaneously. Full overlap ensures seamless layering, critical for fluid textures.
• Position Jitter : Randomizes the grain start position within the source buffer. At 100%, the grains are maximally scattered, avoiding repetition and enhancing spectral variation.

Oscillator

This section introduces internal signal generation and manipulation for tonal shaping:

• Base Frequency: Establishes a carrier tone around which grains may be resynthesized or modulated.
• Pitch Spread: Applies random or distributed pitch offsets across grains. This detunes grains relative to one another, broadening the spectral image.
• Waveform Mix : Blends between oscillator waveforms (e.g. sine, square, saw), adjusting harmonic content.
• FM Amount: Modulates the base oscillator with another signal (usually high-frequency). High values introduce spectral sidebands and increased complexity per grain.

Envelope

Each grain is shaped by an amplitude envelope:

• Envelope (in Audio Synthesis)
• An envelope is a time-based function that modulates the amplitude (loudness) or other parameters of a sound over its duration. It defines how a sound evolves from the moment it begins to when it ends.
• The most common envelope model is the ADSR envelope, which consists of four stages:
• Attack – Time taken for the sound to rise from silence to its peak level when a note is triggered.
• Decay – Time for the sound to drop from the peak level to the sustain level.
• Sustain – The steady amplitude level held while the note is sustained (not a time, but a level).
• Release – Time it takes for the sound to fade from the sustain level to silence after the note is released.
• In granular synthesis, the envelope is applied to each grain individually:
• Short attack and release values yield sharp, transient-rich grains.
• Longer values can produce smoother, more legato-like textures.
• The envelope prevents abrupt changes in amplitude, which would otherwise introduce clicks or artifacts.
• Each grain, though brief, is shaped by its envelope to control how it enters, sustains, and exits the audio stream.

Modulation

This section introduces low-frequency and stochastic modulation of parameters:

• LFO Rate : Governs the frequency of cyclic modulation. At 2 Hz, modulation is slow and perceptible.
• LFO → Pitch / Rate: Currently disabled; would otherwise apply cyclical variation to grain pitch or rate.
• Random Amount: Injects probabilistic variation into modulation targets, adding subtle irregularity.
• Pan Jitter: Maximally randomizes stereo panning of individual grains, distributing sound spatially across the stereo field.