In today’s Gear That Made Us we feature one of our least-successful but most-creative pieces of gear, the Ambiophony system.

Designed by the head of EMI research labs Dr. Gilbert F. Dutton, the system was installed in Studio One in August 1965. It consisted of around 100 speakers evenly spaced on the walls of the studio and a rotating metal drum known as the delay drum.

In a massive feedback loop, sound in the studio would be picked up by microphones, fed into the delay drum, sent back to the speakers on the walls and captured by the microphones again. This was intended to raise Studio One’s 2.4-second reverb time which was relatively short compared to other orchestral spaces.

Check out these amazing technical documents for the Ambiophony system:

Legend has it that 55 years ago today, the Ambiophony system was used by engineer Geoff Emerick on one of the most celebrated Abbey Road sessions of all time. At 8pm on 10 February 1967, a group of forty orchestral musicians arrived in evening dress to record the great crescendo at the end of A Day In The Life. In contrasting psychedelic attire were The Beatles, most of The Rolling Stones, Marianne Faithful, Pattie Boyd, Michael Nesmith, Donavan and Simon and Marijke of The Fool.

George Martin had instructed each instrument to start at the lowest possible note, and, over twenty-four bars, work their way up to the highest note near an E major chord.

“Everyone was to start as quietly as possible, almost inaudibly, and end in a (metaphorically) lung-bursting tumult. And in addition to this extraordinary of musical gymnastics, I told them that they were to disobey the most fundamental rule of the orchestra. They were not to listen to their neighbours.” - George Martin All You Need Is Ears


See if you can spot the Ambiophony speakers on the walls from video footage shot on the day!

The orchestral overdub was only possible because technical engineer Ken Townsend had just made an important technological advancement; a way to make two Studer J37 tape machines run in unison.

“George Martin came up to me that morning and said to me ‘Oh Ken, I’ve got a poser for you. I want to run two four-track tape machines together this evening. I know it’s never been done before, can you do it?’ So I went away and came up with a method whereby we fed a 50 cycle tone from the track of one machine then raised its voltage to drive the capstan motor of the second, thus running the two in sync. Like all these things, the ideas either work first time or not at all. This one worked first time.” Ken Townsend in The Complete Beatles Recording Sessions by Mark Lewisohn

With Ken’s new tape machine discovery and Geoff’s apparent use of the Ambiophony speakers for the live recording, it was a truly progressive session full of not only musical, but also technological creativity.

Despite its use on this unique session, the Ambiophony effect was very difficult to set up and would often feedback in the studio. In 1971 it was removed and the room itself was altered to achieve a reverb time of 3.2 seconds. Now unchanged for over 50 years, Studio One remains one of the best orchestral recording spaces in the world.