The last time I saw John Cale, a significant percentage of the audience missed one of his best numbers. Before Cale and his band came on stage, the house music faded down and was replaced by a single tone, which grew in volume. Listening into it, you could hear harmonics shifting, textures being played with, a very slow pulse.

Whether he was doing it live, or it was a recording, Cale was making this sound with his viola, the instrument he’d played as a teenager in Wales. The shifting harmonics came from drone techniques he’d learned from masters such as LaMonte Young and Tony Conrad, his co-conspirators in the downtown New York avant-garde scene of the mid-1960s.

Cale has never lost his penchant for sonic experimentation. Somewhere I have a bootleg of a tape of Cale and Lou Reed, in the days just before the Velvet Underground came into existence, exploring drones at high volume in a Lower East Side apartment. Casting the decisive vote on whether the piece should continue were a couple of firemen from the firehouse next door, whose arrival halted the experimental piece.

It’s through the Velvet Underground that Cale is best known these days, though his tenure with that influential band lasted for just two of its four albums. His viola drones propelled such songs as “Venus in Furs,” and his knack for experimentation gave us “The Gift.” There’s undoubtedly an equation in physics to explain why two such gifted but unstable creative elements as Lou Reed and John Cale can’t coexist in the same band at the same time, but by 1968, Cale was on his own.

Cale subsequently produced The Stooges’ 1969 self-titled debut and fellow ex-Velvet Nico’s 1970 album Desertshore. He launched his solo career on Columbia with 1970’s Vintage Violence, on which he was backed by the Woodstock, N.Y., band Grinderswitch. The title notwithstanding, it’s almost peaceful at times, especially the song about nuclear obliteration, “Big White Cloud.”

After a 1971 collaboration with experimental composer Terry Riley titled Church of Anthrax, which wasn’t about to set any sales records, Warner Bros. hired him to do production and A&R work. As an artist, he gave them a masterpiece, Paris 1919, which still sounds great today, and he still does some of its songs in concert. Bands who’ve since covered its songs include Superchunk (“A Child’s Christmas in Wales”) and Yo La Tengo (“Andalucia” and “Hanky Panky Nohow”).

From there, Cale moved to Island Records, where he did more great work, including 1974’s Fear (the title song, he has said, “is about working for Warners”) and 1975’s Slow Dazzle. The latter contained his terrifying version of “Heartbreak Hotel,” which served as a reminder that the song came about when its writer, Mae Boren Axton, a schoolteacher at the time, intercepted a student’s suicide note that read, in part, “I walk a lonely street.” As a producer, Cale made his mark with Patti Smith’s landmark debut album (1975’s Horses), along with the self-titled debut LPs of The Modern Lovers (1976) and Squeeze (1978).

As Cale’s reputation for searing, take-no-prisoners shows and songs with attractively enigmatic lyrics grew, he was also crafting soundtracks to European films and collaborating with the likes of Brian Eno and Bob Neuwirth. He even made peace with Lou Reed in 1990 to record a song cycle celebrating the life of their former patron Andy Warhol, Songs for Drella. He’s continued making albums under his own name as well; the latest, Shifty Adventures In Nookie Wood, came out late last year.

In 2010, Cale received the Order of the British Empire from Queen Elizabeth at her annual Birthday Honors ceremony. It’s hard to say which was more surprising: that he got the award, or that, for the occasion, he dyed his hair pink. But one thing that shouldn’t surprise anyone going to see John Cale at Hopscotch is the fact that, at age 71, he’ll be pushing a band half his age to keep up with him as he blasts through a set showcasing 40 years of a career that shows no sign of settling into anything comfortable.

This article appeared in print with the headline “Vintage viola.”

Ed Ward has been rock ‘n’ roll historian for NPR’s Fresh Air with Terry Gross for more than 25 years. He currently inhabits a tiny slum apartment in the south of France.