May, Mercury, and Taylor reportedly sang their vocal parts continually for ten to twelve hours a day.[19] The entire piece took three weeks to record, and in some sections featured 180 separate overdubs.[23] Since the studios of the time only offered 24-track analog tape, it was necessary for the three to overdub themselves many times and "bounce" these down to successive sub-mixes. In the end, eighth-generation tapes were used.[22] The various sections of tape containing the desired sub-mixes had to be spliced (cut and assembled in the correct sequence). May recalled placing a tape in front of the light and being able to see through it, as the tape had been used so many times.[25] A similar story was told in 1977 by Taylor regarding the elaborate overdubs and sub-mixes for "The March of The Black Queen" for the album Queen II. At that time, the band was using 16-track equipment.[26]

Producer Baker recalls that May's solo was done on only one track, rather than recording multiple tracks. May stated that he wanted to compose "a little tune that would be a counterpart to the main melody; I didn't just want to play the melody". The guitarist said that his better material stems from this way of working: in which he thought of the tune before playing it: "the fingers tend to be predictable unless being led by the brain."[19] According to Baker, "the end of the song was much heavier because it was one of the first mixes to be done with automation... If you really listen to it, the ballad starts off clean, and as the opera section gets louder and louder, the vocals get more and more distorted. You can still hear this on the CD. They are clearly distorted."[24]
https://en.wikipedia.org/wiki/Bohemian_Rhapsody