ELI5 how the lyrics to a song can be changed after its recorded.

In addition to what's already been said, when someone talks about the 'master tapes' of a recording, they are talking about the raw multi-track recordings from the studio. What you hear in a song on the radio has a constantly shifting mix (relative volume of each instrument) and has had various effects added to the tracks and may have additional instruments not recorded by the original band members. This version is assembled by the engineer and producer and may sound very different from what the band would play live. For example on one of the albums I've played on there is a lot of little bits of rock organ added by the producer to fill out the sound, but we didn't have a keyboard player when we performed live.

/r/explainlikeimfive Thread