Although effects had been applied to vocals before The Beatles (see below: Pete Drake’s talkbox), nothing like “Tomorrow Never Knows” had been heard before in pop music history. A suggestion from John Lennon on the first day of the Revolver sessions initiated radical rethinking of how vocals were processed. Lennon wanted to sound like the “Dalai Lama singing from the highest mountain top.” In response, Abbey Road’s sound engineer Geoff Emerick basically hacked a Hammond Organ’s Leslie speaker, running Lennon’s vocals through it so that the rotating speaker created a tremolo and chorus effect.
The Leslie effect itself didn’t become ubiquitous on recordings after “Tomorrow Never Knows,” but The Beatles’ adventurous approach to vocals inspired other musical artists to experiment. As the psychedelic era unfolded, vocals quickly become processed with more reverb, slapback delay, flanging and phaser effects, on top of being multi-tracked for other interesting sonic effects (think of the affected vocals on 13th Floor Elevators’ “Slip Inside This House” or the tremolo effect on Tommy James’ vocals in “Crimson and Clover”). And by the late 1960s, the Talkbox was popularized (more on that below).
But the sonic experimentation with vocals didn’t end with the Leslie speaker. Ken Townshend, Abbey Road’s lead recording engineer, developed automatic double tracking (ADT) because Lennon disliked having to sing a vocal twice. While Townshend did manual double tracking on “Tomorrow Never Knows,” the rest of Revolver features a lot of ADT on The Beatles’ vocals. So while “Tomorrow Never Knows” can’t claim to be the first track with ADT, it had a very central role with Townshend developing it.
It’s almost unfair to say “Strawberry Wine” is the song that redefined how some vocals were being produced in the late 80s and early 90s, given all of the iconoclasm of the My Bloody Valentine albums Isn’t Anything (1988) and Loveless (1991). But “Strawberry Wine,” the lead track off of the 1987 eponymous three-song single, is the first time that MBV’s Belinda Butcher and Kevin Shields took on the role of vocalists, doing so by burying their vocals in the mix.
The effect, even though not fully exploited until later EPs and LPs, caused a major ripple, as many bands across the world began recording and mixing vocals in this way. (It’s worth noting that MBV weren’t the first do this—REM’s first few records were notable for how low the band mixed Michael Stipe’s vocals.) The lyrics are near indecipherable, and Butcher and Shields both came off as sleepy, dreamy and druggy. But this approach also made their voices blend into the wall of sound, turning them into instruments in their own right.