Mike Beigel

Michael Lee Beigel was born in New York City on 29 January 1947 to Jerome and Freda Beigel. Music and electronics drew him from an early age: he played clarinet and saxophone, and at 14 he bought an oscilloscope and began teaching himself wave theory.

He weighed a place at the Manhattan School of Music but chose engineering, and was accepted by the Massachusetts Institute of Technology at 17. He graduated as the first MIT student to double major in electronic music, with degrees in electrical engineering and in humanities and engineering.

While still at MIT, Beigel became president of Identic Data Inc., a research and development company set up to create new inventions and product designs. He was developing a synthesizer for Guild Guitars when the project was shelved, and in 1972 he and Aaron Newman, a former Guild engineer, founded the Musitronics Corporation in Rosemont, New Jersey, to save what they could of it. Their first product, built from sections of the synthesizer in the summer of 1972, was the Mu-Tron III envelope filter. Beigel said he chose the envelope filter because it sounded the most musical of the synthesizer's elements and was easy to use.

The Mu-Tron III was taken up on guitar, bass and keyboards. Stevie Wonder used it on his Clavinet for "Higher Ground", and Jerry Garcia, Bootsy Collins, Frank Zappa, Joe Zawinul, Larry Coryell and Chick Corea were among the other musicians who used his designs. Musitronics followed it with the Bi-Phase, Phasor, Phasor II, Octave Divider, Flanger and Vol-Wah pedal, worked with Dan Armstrong's circle on the Green Ringer and the Armstrong plug-in effects, and produced the Gizmo, or Gizmotron. High costs and the failure of the Gizmotron brought the company down, and it was sold to ARP Instruments, which folded soon after.

Beigel carried on through Beigel Sound Lab, whose 1979 envelope controlled filter later returned as the Electro-Harmonix Bi-Filter. In 1995 he designed the Q-Tron for Electro-Harmonix, an update of his original circuit, and he collaborated on products including the Resynator and the Orange Squeezer. In 2014 his company Mu-FX released the Tru-Tron 3X, a refined version of the Mu-Tron III, followed by the smaller Micro-Tron 3. He held about 45 US patents.

He also had a second career in radio frequency identification. As a consultant for AVID, American Veterinary Identification Devices, he developed and directed early manufacturing of RFID products used to identify lost pets. He then designed an RFID penguin weighbridge that recorded the identity and weight of Adelie penguins for the New Zealand Antarctic Programme and the US Antarctic Program of the National Science Foundation, travelling to Antarctica several times to test it, and later adapted the system to track endangered tortoises in the Mojave Desert.

In 2025 he received a Certificate of Recognition from the Recording Academy for his achievements in music engineering and innovation, and on 9 June 2025 he was interviewed for the NAMM Oral History Program.

Beigel enjoyed photography, travel, gardening, backyard bird watching and water sports including windsurfing, surfing and boogie boarding. He loved animals and over his life kept many cats, birds, fish, tortoises, turtles and lizards, and one much loved dog. He had one daughter, Romy, an industrial engineer. His family's obituary noted that for most of her life he lived with Dercum's disease, a rare chronic condition.

Beigel died peacefully at home on 21 September 2026, aged 79. No cause of death was made public. His family announced his death in a statement carried by the music press, and his obituary was published by Barton Family Funeral Service. Tributes came from Jambands, Sound On Sound and the trade magazine MMR, and NAMM recorded his death in its oral history library.

His family wrote that, music aside, he was a beloved father and a friend to many, and that the resonance of his life, in the sounds he shaped and the connections he made, would endure. They asked admirers to support Forgotten Futures, which has worked with the family since 2025 to preserve his prototypes.

The Mu-Tron III helped establish the envelope filter as an enduring category of musical effect, and its sound is closely associated with the funk, rock and jazz of the 1970s. Its descendants, including the Electro-Harmonix Q-Tron and the Mu-FX Tru-Tron 3X, kept his design in production for decades, and his family described his sounds as cemented into music history through the hit songs made with his products. His prototypes are being preserved by Forgotten Futures.