Signum Audio is an Edinburgh-based audio software developer founded in 2017 by two former Rockstar North audio developers. The company focuses on loudness metering, limiting, and normalisation tools aimed at mixing, mastering, post-production, and broadcast workflows, positioning itself within the pro-audio plugin market alongside other specialist loudness and dynamics developers.

Its flagship BUTE range includes the BUTE Loudness Analyser, BUTE Limiter 2, BUTE Loudness Normaliser, BUTE Loudness Suite, and the BUTE Batch Processor, which together cover true-peak metering, brickwall limiting, and offline loudness-compliant file processing. The company has also released the SKYE line, including SKYE Dynamics and SKYE Clipper, expanding its catalogue into broader dynamics and clipping tools.

Signum Audio's plugins are distributed directly through its website and via third-party retailers such as Plugin Boutique, PluginFox, Loot Audio, and ADSR Sounds. Reviews in outlets like Sound on Sound and MusicRadar have highlighted the BUTE line's focus on transparent limiting and detailed loudness analysis for engineers working to broadcast standards such as EBU R128 and ATSC A/85.

Signum Audio has 12 products cataloged on Equipboard, including Compressor Plugins, Mastering Plugins, and Limiter Plugins.