Recently I have been working with a Japanese company that creates karaoke guide vocals and harmonies for karaoke booths. As they can't use the voice of the original artists all the vocal layers of a track need to be recorded. It can be quite a challenge to sing a vocal line with the exact pitch and timing as the original artist. You become aware of the points when the notes are not quite in tune, or when a word is pronounced in an unusual manner, or when the an artist does or doesn't use vibrato. It is not surprising that artists like Celine Dion and Barbara Streisand are hard to copy, but I was not expecting Abba to have so many vocal parts in their songs.
It is very precise work but I have been enjoying the challenge. It's also fun to hear my own voice played back when I have recorded 11 vocal parts for one chorus of a song.