Wondering Sound reports that the pioneering rap producer Larry Smith, the man responsible for Run-D.M.C.’s simple and crushing sound, has died. The longtime rap insider Combat Jack spread the word on Twitter after speaking with Smith’s family. Smith was 63.

Smith, who grew up in Queens, started out as a session musician. In 1979, he played bass on “Christmas Rappin’,” a single from the early rap star Kurtis Blow. He would go on to play bass on and co-write many of Blow’s songs, including “The Breaks,” one of the first rap singles ever to make a dent on the American charts. Through Blow, Smith met Russell Simmons, who was then Blow’s manager. And together, Simmons and Smith would produce a couple of singles for Jimmy Spicer, including the influential and oft-sampled “Money (Dollar Bill Y’All).” But they’d find their greatest success when they started working with Simmons’ brother’s group, Run-D.M.C.

Smith and Simmons co-produced “It’s Like That” b/w “Sucker MCs,” Run-D.M.C.’s first single, and in doing so changed the sound of recorded rap. Before that song, rap groups, like the ones on the Sugar Hill label, used session musicians (like Smith) to give their records a lush, disco-friendly feel. Smith instead used drum machines, giving Run-D.M.C. a huge, brutal, simplistic sound, making the rappers sound harsh and immediate. Run-D.M.C. went on to become the most successful group that rap had ever seen, and Smith and Simmons co-produced their first two albums, 1984’s self-titled debut and 1985’s King Of Rock. Smith changed rap again when he brought in a friend, the rock guitarist Eddie Martinez, to lay hair-metal riffs all over some of Run-D.M.C.’s singles, thus paving the way for every rap/rock crossover that would follow, including the rock-sampling work of Rick Rubin. (Rubin would take over as Simmons’ Run-D.M.C. co-producer on the group’s third album, 1986’s Raising Hell.)

Without Simmons, Smith also produced the first two albums from the Brooklyn trio Whodini, 1984’s Escape and 1986’s Back In Black. Compared to his work with Run-D.M.C., Smith’s production for Whodini was fast and bubbly, and it yielded nearly as many classic singles: “Friends,” “Five Minutes Of Funk,” “Freaks Come Out At Night.” Smith didn’t like sampling, though, and his style had fallen out of favor by the sample-heavy late ’80s. In recent years, he suffered a stroke that left him unable to speak, and he lived in a nursing home, according to this Medium article about his life.

Below, listen to some of the tracks that Smith produced or co-produced.