ugen

A unit generator (UGen) is a fundamental building block in digital audio synthesis. It is a self-contained DSP block that either generates an audio signal, processes a signal, or both. UGens are typically evaluated in real time and can produce outputs at audio rate (per sample) or control rate (per block), with the latter often used to modulate parameters and reduce processing load.

UGens are combined into graphs to form synthesizers. The output of one UGen can feed the input of another, creating a signal flow from source to output. Common categories include oscillators (generating waveforms such as sine, square, or saw), noise generators, envelopes and LFOs, filters, delays, reverbs, and various DSP effects. Many environments use the term UGen as the generic label for these units; blocks can be built-in or user-defined.

In practice, UGens are central in environments like SuperCollider and Csound, where they are the basic objects for sound design. They can run on dedicated audio servers and are often arranged into synth definitions or instruments. Users connect UGens to shape timbre, dynamics, and spatialization, using envelope control, pitch, and amplitude routing.

The term unit generator emphasizes the modular, compositional nature of synthesis, contrasting with higher-level abstractions. It remains a standard concept in modern digital audio workstations and programming languages that support real-time synthesis.