Metasonix is an audio equipment manufacturer based in Lakeport, California, founded by Eric Barbour in 1998. The company designs synthesizers, effects, and amplifiers built around atypical vintage vacuum tubes — often industrial, military, or television tubes that were never intended for audio use. The resulting instruments are known for being aggressive, unpredictable, and sonically extreme, occupying a niche far removed from the polished sound of mainstream analog gear.

The catalog includes Eurorack modules such as the RK2 XS-VCA, RK3 Ringer/Shaper, RK4 Filter/VCO, RK6 Resonant Lowpass Filter, RK7 VCO, and RK8 Filterwall, alongside standalone instruments like the S-1000 Wretch Machine semi-modular synthesizer, the D-2000 vacuum tube drum machine, and the T1 three-oscillator tube synthesizer in a wood case. Earlier products such as the TM-7 Scrotum Smasher distortion preamp, TX-1 Agonizer, TX-2 Butt Probe, and the G-1000 guitar amplifier helped establish the company's reputation for provocative naming and uncompromising tube-based design.

Metasonix gear is generally high-priced, power-hungry, and oriented toward experimental, noise, and industrial musicians rather than conventional players. Eric Barbour, who also writes about tube technology, is regarded within the modular synthesis community as an authority on repurposing obscure tubes for musical use, and the brand has built a cult following among modular and Eurorack enthusiasts seeking sounds that other manufacturers can't or won't produce.

Metasonix has 17 products cataloged on Equipboard, including Modular Synthesizers, Fuzz Effects Pedals, and Distortion Effects Pedals. Their gear is featured by 19 artists, with the strongest followings in Electronic, Rock, and Pop. Notable users include Trent Reznor, Mick Gordon, and Deadmau5.