The Matrix was a nightclub in San Francisco from 1965 to 1972 and was one of the keys to what eventually became known as the "San Francisco sound" in rock music. Located at 3138 Fillmore Street, in a 100-capacity beer-and-pizza shop, The Matrix opened 13 August 1965, showcasing Jefferson Airplane, which singer Marty Balin had put together as the club's "house band". Balin had persuaded three limited partners to put up $3,000 apiece to finance the club's opening, giving them 75 percent ownership, while he retained 25 percent for creating and managing it.

The San Francisco sound refers to rock music performed live and recorded by San Francisco-based rock groups of the mid-1960s to early 1970s. It was associated with the counterculture community in San Francisco, particularly the Haight-Ashbury district, during these years. San Francisco is a westward-looking port city, a city that at the time was 'big enough' but not manic like New York City or spread out like Los Angeles. Hence, it could support a 'scene'. According to journalist Ed Vulliamy, "A core of Haight Ashbury bands played with each other, for each other"