abstract:A mix engineer or mixing engineer is a person responsible for combining ("mixing") the different sonic elements of a piece of recorded music (vocals, instruments, effects etc.) into a final version of a song (also known as "final mix" or "mixdown").
In the late '70s, when 24-track recording was possible but there was no reliable way to automate mixing, mixing records was a live performance, with the producer, the engineer and half the band called in to push faders up and down as the track was bounced to the master tape.