 The resulting Monterey Pop Festival was held during June 16–18, 1967.Jacob designed the sound system for the whole festival, and he incorporated the stage requirements of the various bands on the bill, after which he determined that he would need a total of 24 microphone inputs on his mixer, which was unheard of at the time.He augmented the proprietary 16-channel stereo sound console designed by McCune head engineer Bob Cavin with two 4-channel mono Altec 1567 tube mixers to get 24 inputs.