Here's a method of recording backing vocals, on GarageBand for iOS 10 / 11, but really it applies to any recording device/software.
After this one, see part TWO for mixing and saving tracks.
In this video, I record five-part harmonies, with three tracks per harmony part to achieve a choir effect. Firstly, backing vocals as sound effects, and then backing vocal lyrics.
Timings shown below:
2:30 prepping for recording - level setting
3:10 recording the first backing vocal
3:30 why record two more of the same harmony part?
5:20 panning the three tracks recorded so far
13:10 listening back to the entire backing vocals - editing, mixing, effects, etc.
18:10 backing vocal lyrics - the importance of timing precision
22:47 basic audio editing - trimming tracks
23:45 fixing timing problems with splitting tracks
Stick with it! There are plenty of tips for the recording musician here...
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