In the studio

The Beatles’ previous album, Rubber Soul, had seen them exploring R&B and folk stylings. Revolver took this further, bringing in influences such as Motown, classical Indian music and children’s songs, in addition to orchestral instrumentation and elements of musique concrète.

Revolver was accepted well. I don’t see too much different between Rubber Soul and Revolver. To me, they could be Volume One and Volume Two.
George Harrison

There were four main sonic innovations on Revolver. The first of these was the use of artificial double tracking, or ADT. This was invented by EMI engineer Ken Townsend in April 1966, and involved linking two tape machines to create a doubled vocal track. Due to minute differences in playback, the two recordings would separate slightly, giving the effect of two voices when combined.

ADT was used extensively on Revolver, and quickly became an established pop production technique. John Lennon, in particular, was delighted with the invention, as he always found manually double-tracking his vocals a laborious process, and George Harrison reportedly told Townsend he should have been given a medal for creating it.

Lennon – never the most technically-minded of musicians – once asked George Martin to explain how ADT worked.

I knew he’d never understand it, so I said ‘Now listen, it’s very simple. We take the original image and we split it through a double vibrocated sploshing flange with double negative feedback…’ He said ‘You’re pulling my leg. Aren’t you?’ I replied ‘Well, let’s flange it again and see’. From that moment on, whenever he wanted ADT he would ask for his voice to be flanged, or call out for ‘Ken’s flanger.’
George Martin
The Complete Beatles Recording Sessions, Mark Lewisohn

A by-product of ADT was the ability to speed up and slow down recordings via a dedicated oscillator. The Beatles found that varispeeding a recording changed the texture of sound, which they put to extensive use during the Revolver sessions.

The second key innovation was the use of backwards recording. This had actually been first used in a non-Revolver song, ‘Rain’, the b-side of ‘Paperback Writer’. The backwards vocals which ended Rain were recorded on 14 April 1966.

Revolver very rapidly became the album where the Beatles would say ‘OK, that sounds great, now let’s play it backwards or speeded up or slowed down’. They tried everything backwards, just to see what things sounded like.
Geoff Emerick
The Complete Beatles Recording Sessions, Mark Lewisohn

Two songs on Revolver featured backwards recordings: ‘I’m Only Sleeping’ and ‘Tomorrow Never Knows’. While the latter predominantly used tape loops, ‘I’m Only Sleeping’ saw The Beatles spend six hours creating the two simultaneous backwards lead guitar parts. They were recorded on 5 May 1966.

Of all the songs on Revolver, none was more innovative than the album’s closing song, ‘Tomorrow Never Knows’. The song was a giant leap forward for The Beatles, with its thunderous drum sound, lyrics adapted from Timothy Leary and Richard Alpert’s adaptation of the Tibetan Book of the Dead, use of tape loops and Leslie speakers.

The tape loops were overlaid onto the backing track. Six loops were used on ‘Tomorrow Never Knows’: a seagull noise, actually a distorted recording of Paul McCartney laughing; an orchestra playing a B flat chord; notes played on a Mellotron’s flute setting; a second Mellotron on its violin setting; and a distorted sitar which is most clearly heard in the instrumental break following the lines “It is being, it is being”. A guitar solo by McCartney, reversed and slowed down a tone, was also used in the instrumental break.

The final remarkable innovation in ‘Tomorrow Never Knows’ was John Lennon’s voice. For the first half of the song he manually double-tracked his vocals. For the song’s second half, meanwhile, the Abbey Road engineers ran Lennon’s voice through a revolving Leslie speaker, more commonly found inside Hammond organs. It can be heard from the line ‘Love is all and love is everyone’ onwards.

Lennon had an idea of how he wanted the song to sound, but it was down to George Martin and the studio engineers to realise the vision. Chief among the EMI Studios staff was Geoff Emerick, the young engineer who played a crucial role in developing The Beatles’ sound between 1966 and 1968.

For ‘Tomorrow Never Knows’ he said to me he wanted his voice to sound like the Dalai Lama chanting from a hilltop, and I said, ‘It’s a bit expensive, going to Tibet. Can we make do with it here?’ I knew perfectly well that ordinary echo or reverb wouldn’t work, because it would just put a very distant voice on. We needed to have something a bit weird and metallic…

A Leslie speaker is a rotating speaker, a Hammond console, and the speed at which it rotates can be varied according to a knob on the control. By putting his voice through that and then recoding it again, you got a kind of intermittent vibrato effect, which is what we hear on ‘Tomorrow Never Knows’. I don’t think anyone had done that before. It was quite a revolutionary track for Revolver.

George Martin