ATOC (Automatic Transient Overload Control) #GearThatMadeUs

9th December 2021

For today’s Gear That Made Us we’re highlighting the ATOC (Automatic Transient Overload Control, TG12330), an elusive mastering tool specially designed for Abbey Road in the mid-‘60s.

This EMI device was used to prevent low-frequency overload when cutting a master disc. As its flashing lights blinked, the ATOC would read and respond to peaks in the audio signal by automatically turning the level down, thereby saving the lacquer master. It allowed mastering engineer Tony Clark to cut The BeatlesPaperback Writer with an extremely high bass factor without causing the needle on a record player to jump.

"Clark used EMI’s newly-acquired ATOC system to cut probably one of the loudest masters EMI had created up to that point."

"I remember the buzz that quickly went around Abbey Road when it became apparent what we had achieved with the sound of a record. People were standing outside the door and listening…It was so different; really it was like seeing the first screening of 2001.” Geoff Emerick from Recording The Beatles by Brian Kehew & Kevin Ryan

It remained the standard for disc-cutting at EMI until the mid-‘70s...

Mickie Most called me in one day to Harry Moss’s cutting room and showed me the difference with it in and with it out. I think we were cutting the group Mud. It had been mandatory to use it, but rather than lose his valuable cutting work, I immediately had it removed from all cutting rooms.” Ken Townsend from Recording The Beatles by Brian Kehew & Kevin Ryan


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