Audacity's Nyquist prompt lets you write Lisp code to synthesise, analyse, and process audio

Nyquist is a programming language for sound synthesis and analysis based on Lisp, created by Roger Dannenberg at Carnegie Mellon University. Audacity exposes a subset of Nyquist through its Nyquist Prompt, letting users write short programs that operate on selected audio — applying custom DSP, generating signals, or analysing content. Beyond one-off prompts, Nyquist powers Audacity’s entire plugin architecture: third-party effect, generator, and analyzer plugins are plain text .ny files. This turns Audacity from a fixed-feature editor into an extensible platform. A common misconception is that plugin creation requires a full development environment — a .ny file is just a text file with a header and one Lisp expression. The practical entry point is the Nyquist Prompt (Effect > Nyquist Prompt) for experimenting before packaging.

Examples

A one-line Nyquist effect that amplifies by 6 dB: (scale 2 s) — s is the bound variable for the current selection. Saving this with a plugin header as double.ny makes it appear in the Effects menu.

Assessment

Open the Nyquist Prompt in Audacity and write a single expression that reverses the selected audio. Identify which Nyquist variable holds the current selection.