During the 1960s, it became possible for musicians to record audio tracks on top of previously recorded audio tracks. This technology is called multi-tracking and recording over pre-existing audio is called overdubbing. We take this for granted now but the album, "Sgt. Pepper's Lonely Hearts Club Band" (1967) was highly innovative because of the extent to which it did this. At the time it was a very new approach to music making.
Listen to the original take of "When I'm 64" which included a live performance with drums, piano, bass guitar and lead vocals.
Now listen to the second video which is the final mix of the song. After the recording of the drums, piano, bass and vocals was completed, 2 clarinets and a bass clarinet were overdubbed to create one seamless performance, even though the musicians didn't play at the same time.
Acute listeners might also notice the fact that the tape has been sped up and is subsequently a little higher in pitch!
This mini-documentary sees Brian May discussing the studio creation of "Bohemian Rhapsody" using multi-tracking. The recording of Killer Queen was done in a very similar way.
From 1'15 - Brian May talks about the recording of the backing track (piano, bass and drums). It is strange to hear the piano of the intro to the song without all of the overdubbed vocals on top! These were recorded later and the piano was taken off to make the vocals acapella. The operatic section at 4'54 sounds particularly sparse with just piano without all the added vocals.
Brian May explains that the "orchestration" of the guitar overdubs were "adornments" that he added with Freddie's approval. At 11'25 we hear some of these "orchestrations".
The original backing track to Killer Queen consisted of piano, bass and drums.
The following parts and sounds were overdubbed on top of the backing track using multi-tracking:
A honky tonk piano (an out of tune or tack piano) was layered on top of the original piano to create a brittle and jangly sound. It is easy to hear this at bar 3 (0'03) when the piano first plays but it has been overdubbed for the entire duration of the song.
Backing vocals. These are overdubbed and all sung by Freddie! They first come in with vocables at bar 8 (0'15) and then provide the parallel harmonies in the chorus at bar 15 (0'27), bringing a lot of intensity to the song.
Triangle - a single triangle hit can be heard on the downbeat of bar 29 (0'56).
Wind chimes - these can be heard on the word "you" in bar 68 (2'16) which comes across as an eerie example of word painting!
All electric guitar parts were "orchestrated" and overdubbed later. Often this enabled harmonies to be built up, as Freddie did with his vocals. From bar 55 of the guitar solo (1'49) there are 3 guitar parts layered on top which provide textural and harmonic variety.
Panning is a common studio effect that mixes a certain audio track more in the left or right speaker to create a sense of space. Audio which is mixed in this way is called stereo as opposed to mono which is a single mix from one speaker. This is taken a step further in film music with surround sound. This includes mixing sound into a number of speakers, which help provide an even more cinematic experience.
Much of the backing vocal and electric guitar parts were panned to help create the sophisticated mix of the song and to create a sense of contrast.
A good example includes the backing vocals ("ba ba ba ba") in bar 18 (0'34) which are panned to the left and the following word ("anytime") in bar 19 (0'36) which is heard panned right.
Contrastingly, the vocals are panned to the right in bar 66 (2'11) for the lyrics "drive you wild" and are then changed to the left.
Other electronic effects were added to parts in the mix.
Flanger creates a sweeping sound as illustrated in this Youtube video. In Killer Queen, a flanger called the Countryman phase shifter was used. It is usually an electric guitar effect but in Killer Queen, flanger is added to the vocals for a futuristic effect at bar 17 (0'32). This creates word painting for the lyrics, "laser beam".
Wah-wah is an effect which cuts out certain frequencies in the sound to make it sound like the spoken word, "wah"! Brian May uses this effect on his guitar overdubs in bar 62 (verse 3, 2'03) to almost mimic the lyrics, "willing as".