I thought of something just now for people to sing harmonies that dont necessarily know how(like myself). If I want to record vocals for a song I would sing to the root of the chords. To sing harmonies I just play the 3rd of each chord in the chord progression. and then overlap the melody and harmony.

Bish bash bosh and you just recording yourself singing harmonies
^Yeah, but then you've locked yourself into essentially the most predictable melody and vocal harmony EVER.

It works, but it's in no way even close to a substitute.

Just my 2c
"There are two styles of music. Good music and bad music." -Duke Ellington

"If you really think about it, the guitar is a pointless instrument." - Robert Fripp