In the early ’80s, the Roland Corporation, a Japanese electronics company, developed two machines that would soon become obsolete and change the world, in that order. The TR-808 Rhythm Composer and the TB-303 Bass Line — synthesizers with built-in sequencers — were designed for musicians to practice with at home, by programming artificial accompaniment. They used voltage-­controlled oscillators to generate sound waves intended to resemble an acoustic drum set and an electric bass. Sonically harsh and rigid, they were considered largely unsuitable by serious musicians, and they trickled into thrift stores, garage sales and pawn shops. Eventually, they were discovered by D.J.s in the Midwest, who used them to create sounds that no existing instrument was capable of making.

People often forget that the most visionary musical styles to come from America in the late 20th century — house and techno — are not from the coastal capitals of modern culture but the perennially neglected Rust Belt. House was born in Chicago and got its name somewhat incidentally, from a club at the center of the scene called The Warehouse. But the word ‘‘techno’’ was chosen by design: Juan Atkins, a Detroit musician who put out the genre’s first records, named it after a section in Alvin Toffler’s book ‘‘The Third Wave,’’ called ‘‘The Techno-­Rebels.’’ Toffler was describing what we might now refer to as hackers — those who refused to limit their uses of machines to the intentions of their manufacturers.