Chord Substitutions are chords that can be used in place of another. This idea found it’s origins in mainly jazz music. Substitution chords are used to create variety and interest….and perhaps the muso from getting bored.
It would be a great idea to use the standard chords for the first half of a song and then perhaps add some chord substitutions for part of the second half. I probably wouldn’t use substitution chord in a chorus of a song….as I want this to remain very familiar.
Chord Substitutions is something I would like to look a little more into. Still trying to get my head around it. I have done some similar in a way in one of my songs……..where the 2nd time through the song the bass note of the chord was altered creating a new sound.
I found this video most helpful in explaining how Chord Substitutions work.
Comp Studies Blog 