Former high school buddies Keith Barr and Terry Sherwood were in their early twenties and making a living repairing audio equipment from their basement apartment when they founded MXR in 1972. They had been unimpressed with the tone, build quality and general character of existing effects pedals, and sought to bring some colour into the market.
Their initial offering, the Phase 90, quickly became one of the definitive phaser pedals in the guitarist's toolkit. Eddie Van Halen took advantage of its slow subtle sweep to make his guitar solos stand out when dealing with lousy PA systems and lousier sound engineers, and it can be heard on much of his recorded output.
MXR produced one of the first guitar multi-FX units in 1983, the Omni, offering sustain, distortion, delay, equalization, flanger and chorus in a single rackmount unit. Unfortunately, as with many professional audio companies, the early 1980s was a difficult time financially for MXR, leading to the bankruptcy of the company in 1984. Barr left the company to found Alesis, and Sherwood co-founded Applied Research & Technology. Jim Dunlop acquired the rights to the MXR brand and product line, and continues to create straightforward, high-quality effects pedals based on the original designs, as well as some modernized updates.