A lot of guitarists don’t want to learn about music theory. I have always taken a different view. Music theory helps you to talk about music, and to understand how music works. Why wouldn’t any musician want to learn as much as they can about it! It helps to learn the right kind of theory, that can help with the music that you like to play. But there are basics that apply to all music, at least modern popular music, and theory can help you be a better, more creative player. Here’s an example. The other day I was rehearsing with some musicians for a recording session. The aim was to record some songs for an educational program for immigrants. In one song, there was a three part harmony section which just wasn’t sounding right. Four of us were standing around, suggesting one thing and then another, and it still just wasn’t working.
As I wasn’t doing any singing, I was just sitting back, waiting for the vocalists to get themselves organised, when I started thinking about the theory of what they were doing. The progression was G minor to A7, then resolving to a D minor. Turned out the melody line went to an E on the Gm, making it a G minor 6th. The harmony lines just weren’t working, no matter what permutation of G minor was tried.
Theory knowledge kicked in. A G minor 6th has the same notes as an E minor 7th flat 5. The progression becomes a minor ii-V-I progression, a very strong sounding progression. If the voices harmonise an Em7b5 chord, maybe it will sound OK, I thought, and bring out the strong harmonic movement of the ii-V-I. This plan was suggested, duly tried, and bingo, problem solved! A strong vocal harmony while the band comped over the original Gm-A7-Dm progression.
A bit of theory can work the same way for you – and make you a better musician, and a better musical problem solver.