“The most incandescent of the new electric bands" Extremely Rare Matrix, San Francisco poster! Took place 9/7-15/1966. The Matrix, a renovated former pizza shop, 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, The Matrix opened August 13th, 1965 and showcased the most amazing and popular musicians and artists of the time!