Funktion-One is a British professional loudspeaker manufacturer based in Dorking, Surrey, England, founded in 1992 by Tony Andrews and John Newsham after the pair departed Turbosound, the festival sound company they had previously built up from 1978. The company designs and builds large-format point-source PA systems aimed at high-fidelity reproduction in clubs, festivals, and installed venues, and is widely recognized for the distinctive purple cabinets and white 'axehead' mid-range horns that mark its rigs.

Funktion-One's product catalog spans the flagship Vero and Vero VX line-source systems, the Evolution series, the Resolution range (including the compact Res 1, Res 2, and Res 4), the smaller F-Series cabinets such as the F5, BR sub-bass enclosures, and a line of dance-focused subs and infrabass units. Andrews and Newsham hold patents across several generations of loudspeaker designs — the TMS-3, Flashlight, Floodlight, Resolution, Evolution, and Vero among them — and the company emphasizes acoustically flat, minimally processed designs that rely on crossover filters, delays, and gains rather than heavy DSP correction.

The brand is closely associated with electronic dance music culture and has been installed in clubs and venues including Berghain in Berlin, Smartbar in Chicago, De School in Amsterdam, D-Edge in São Paulo, and Hï Ibiza, alongside festival deployments such as Glastonbury and Awakenings. An early high-profile project was the Central Show sound system at London's Millennium Dome.

Funktion One has 3 products cataloged on Equipboard, including DJ Mixers, Speakers & Accessories, and Power Amplifiers. Their gear is featured by 2 artists, with the strongest followings in Electronic. Notable users include Deadmau5 and Underworld.