Theory Question - Available Chords

[clayton.dickmann]

Quick question that I'm guessing is pretty simple but don't know the answer to. Say I'm writing a song in the key of G major. This gives me the notes of G, A, B, C, D, E and F#. Am I able to use a G minor 9th chord and still "conform" to the key, since a Gmin9th would be G, A#, D, F and G? A# and F are obviously note notes available within the key of G major, so does this mean that a G minor 9th is not available for use in the G major chord at all?

Thanks!

[TLW]

I guess it depends on what genre you are writing in and what you want the music to sound like.

A blues soloist happily plays A# and F against a backing band playing the chord of G major all the time. So do many jazz and rock musicians. Avante-guard composers tend not to feel very bound by the formal rules of theory either.

Someone writing two or four part harmony in the baroque or barbershop styles might not be entirely happy at straying out of the home key, but no doubt there are exceptions. And as for music played against a drone, all kinds of “rules” get broken.

The “rules” of musical theory are a guide, they’re not laws never to be broken. In the end it doesn’t matter whether music complies with them or not - what matters is whether it sounds good.

[stringtapper]

A Gm9 in the key of G Major would be an example of modal mixture, which is the borrowing of chords from the parallel minor key in relation to the home key.

It’s usually done the other way, with something in the key of G Minor moving to a G major chord, but the other way happens too. It’s just that it’s going to have a very particular sound and going to be very “striking” to the ear, so it needs to happen in a musical context that warrants it, like a bridge.