Mr. Paul was drafted in 1942 and worked in California for the Armed Forces Radio Service, accompanying Rudy Vallee, Kate Smith and others. When he was discharged in 1943, he was hired as a staff musician for NBC radio in Los Angeles. His trio toured with the Andrews Sisters and backed Nat King Cole and Bing Crosby, with whom he recorded the hit “It’s Been a Long, Long Time” in 1945. Crosby encouraged Mr. Paul to build his own recording studio, and so he did, in his garage in Los Angeles.

There he experimented with recording techniques, using them to create not realistic replicas of a performance but electronically enhanced fabrications. Toying with his mother’s old Victrola had shown him that changing the speed of a recording could alter both pitch and timbre. He could record at half-speed and replay the results at normal speed, creating the illusion of superhuman agility. He altered instrumental textures through microphone positioning and reverberation. Technology and studio effects, he realized, were instruments themselves.

He also noticed that by playing along with previous recordings, he could become a one-man ensemble. As early as his 1948 hit “Lover,” he made elaborate, multilayered recordings, using two acetate disc machines, which demanded that each layer of music be captured in a single take. From discs he moved to magnetic tape, and in the late 1950s he built the first eight-track multitrack recorder. Each track could be recorded and altered separately, without affecting the others. The machine ushered in the modern recording era.

In 1947 Mr. Paul teamed up with Colleen Summers, who had been singing with Gene Autry’s band. He changed her name to Mary Ford, a name found in a telephone book.

They were touring in 1948 when Mr. Paul’s car skidded off an icy bridge. Among his many injuries, his right elbow was shattered; once set, it would be immovable for life. Mr. Paul had it set at an angle, slightly less than 90 degrees, so that he could continue to play guitar.

Mr. Paul, whose first marriage, to the former Virginia Webb, had ended in divorce, married Ms. Ford in 1949. They had a television show, “Les Paul and Mary Ford at Home,” which was broadcast from their living room until 1958. They began recording together, mixing multiple layers of Ms. Ford’s vocals with Mr. Paul’s guitars and effects, and the dizzying results became hits in the early 1950s. Among their more than three dozen hits, “Mockingbird Hill,” “How High the Moon” and “The World Is Waiting for the Sunrise” in 1951 and “Vaya Con Dios” in 1953 were million-sellers.