KV331 Audio is a Turkish music technology company founded in 2004 by Bulent Biyikoglu, an electrical and electronics engineer who previously worked at PG Music and Digidesign (now Avid). The company name references KV 331 in the Köchel catalogue — Mozart's Piano Sonata No. 11. Since its founding, KV331 Audio has focused exclusively on developing the SynthMaster family of software synthesizers, available as VST, VST3, AU, and AAX plugins for Mac and Windows, as well as iOS apps.

The flagship product, SynthMaster 3, is a semi-modular synthesizer supporting a wide range of synthesis methods including virtual analog, additive, wavetable, granular, FM, phase modulation, phase distortion, physical modeling, and SFZ sample playback, with up to 16 layers per patch. SynthMaster One offers a streamlined single-layer wavetable synth aimed at fast workflow, while SynthMaster Player provides a preset-focused experience with access to the full factory library across all SynthMaster versions — over 4,400 presets. SynthMaster was voted the best VST/AU synth in the world in MusicRadar reader polls in both 2016 and 2019.

SynthMaster has been used by electronic music producers including Armin van Buuren, Zedd, Axwell, Martin Solveig, and Roger Sanchez. The synthesizer's preset library features contributions from noted sound designers such as BT, Nori Ubukata (known for his work on the original Yamaha DX series), and Francis Preve.