Herbert A. Deutsch, a composer who collaborated with engineer Robert Moog in the 1960s to invent a portable electronic music synthesizer that revolutionized the sound of rock, classical and other forms of music, died Dec. 9 at his home in Massapequa Park, N.Y. He was 90.

His stepson Daniel Rogge confirmed his death but did not cite a specific cause.

Although the device became known as the Moog synthesizer, Deutsch was by all accounts an instrumental figure in its invention. Moog machines used a piano-like keyboard to synthesize electronic sounds from a cabinet of modules that held voltage-controlled gizmos connected by patch cords.

Before the Moog’s invention in 1964, musical synthesizers existed mostly in university labs, but they were unwieldy and immovable. The Moog, which looked a telephone switchboard, was heavy but mobile. In the late 1960s, musicians began using versions of the device in recording studios and concerts.

The Beatles used a Moog for several songs on their 1969 album “Abbey Road,” including “Here Comes the Sun” and “Because.” The Doors, The Monkees, Pink Floyd and the Rolling Stones used Moog devices too, as did Keith Emerson, Donna Summer and Stevie Wonder. Classical pianist Wendy Carlos used the machine to rework several compositions by Johann Sebastian Bach in “Switched-On Bach” (1968), for which she won a Grammy.

By the 1970s, Moog devices were being used across the music industry – in disco, dance, hip-hop, and beyond.

“Moog’s machines entertained a generation that welcomed musical innovation, not to mention bong-loads of black opiated hashish,” Washington Post reporter Richard Leiby wrote in 2000 in an appreciation of the machine. “A tangle of patch cords and modules that could replicate and invent a wide range of tones, also launched a sonic revolution.”

Deutsch and Moog first met in 1963 at a music conference in New York. Deutsch, a trained composer, was teaching music history and theory at Hofstra University. Moog was a doctoral student in engineering at Cornell. Deutsch had been dabbling in electronic music and at the conference, he saw Moog selling kits to make theremins, an electronic instrument that emits an eerie sound almost like a wailing human voice or a siren.

A year earlier, Deutsch had used one of Moog’s kits to build his own theremin. They chatted about theremins for a bit and then more broadly about music. “While Moog was a brilliant engineer, he didn’t really know what I meant when I said ‘electronic music,'” Deutsch recalled in a history of his involvement with the machine. “At that time, it was the concept of being, of putting these into a musical world as concert pieces that Bob really didn’t know about.”

A couple of months later, Moog attended a concert Deutsch put on in New York City at the studio of sculptor Jason Seley, who welded automobile bumpers. Deutsch played a mix tape of electronic sounds while other musicians banged on various items in Seley’s studio. “A sculptural medley with echoes of the anto-repair shop!” wrote a New Yorker reporter who was in attendance. “Another sculpture took voice, and another. Louder and louder rang the bumpers.”

Moog was astounded and impressed.

Afterward, they had dinner and began discussing the project that ultimately became the Moog synthesizer. “He was the electrical engineer; I was the musician,” Deutsch told the New York Times in 2007. “I’d say, ‘Can we do this?’ And he’d say, ‘Sure.'”

As Moog worked on the electronics, Deutsch began composing a piece to play on it. He also made suggestions to Moog about how the machine should work, including using a keyboard – a simple interface any musician could use – to trigger sounds.

“If there had been no Herb Deutsch, the history of the synthesizer would have looked quite different, because you wouldn’t have had the keyboard,” Trevor Pinch, the co-author of “Analog Days: The Invention and Impact of the Moog Synthesizer,” told the New York Times. “Herb Deutsch’s involvement was crucial.”

The Moog synthesizer went on sale in 1964, and Moog, who died in 2005, continued to refine it, introducing a smaller version in 1970 called the Minimoog.

Herbert Arnold Deutsch was born in Hempstead, N.Y., on Feb. 9, 1932. His family was poor and owned a chicken farm. They had a piano that wouldn’t play.

“When my musical life began, I really didn’t know what it was,” Deutsch recalled in a history of his life on Moog Music’s website. “What I do remember: I was three years old, and I was out in the garage by my house. I was standing there with a stick in my hand, and with that stick, I was hitting the ground. As I moved the stick, I knew that it was changing pitch. And so I figured, ‘Oh, if I keep moving this stick around, it goes bum, bum, bum, bum, bum,’ and I heard that.”

Deutsch was introduced to electronic music as a college student at Hofstra, where he studied music education. One of his professors gave him a recording of electronic music by composer Vladimir Ussachevsky.

“I took that recording home, and I remember distinctly putting it on a record player, turning all the lights out, and sitting in the darkness listening to this new sound of electronics,” Deutsch said in a 2015 interview with the Henry Ford Museum of American Innovation. “I fell in love with it right away.”

Deutsch graduated from Hofstra in 1956 and then enrolled at the Manhattan School of Music, where he earned a bachelor’s and master’s degree in music. He pursued a doctoral degree at New York University but didn’t finish. In the early 1960s, he began teaching at Hofstra, where he chaired the music department before retiring in 2018.

Deutsch was married to the former Margaret Carbray from 1960 until her death in 1996. The next year, he married Nancy DiNapoli.

In addition to his wife, survivors include two children from his first marriage, Lisbeth Mitchell of Huntington, N.Y., and Edmund Deutsch of Bayport, N.Y.; three stepchildren, Cheryl Sterling of Ridgewood, N.J., Adam Blau of Los Angeles and Daniel Rogge of Seattle; nine grandchildren; and two great-grandchildren.

Versions of Moog synthesizers have been used contemporary artists such as Cold Play, Nine Inch Nails, and Dr. Dre.

Deutsch and Moog stopped working together after 1970. They had professional disagreements but later reconciled as friends, according to the New York Times.

Even though Moog’s name, not his, is on the machines, Deutsch told the Times that “it hasn’t kept me from being who I am.”

“It’s always exciting to know that I’ve been a piece of music history – that I was there,” he said.