Sequential Circuits was an American synthesizer company founded in 1978 by Dave Smith. It played a significant role in the development of electronic music instruments, particularly known for its innovative products like the Prophet-5, one of the first programmable polyphonic synthesizers. The company was influential in the 1980s, contributing to the rise of MIDI (Musical Instrument Digital Interface), which allowed different electronic instruments to communicate with each other. Sequential Circuits was eventually acquired by Yamaha in 1987, but its legacy continues to impact music technology today.