Many guitarists avoid music theory for various reasons. Maybe because its rare to see great guitarists thanking their knowledge of music theory as the reason they became successful but perhaps they should. Music theory can save you a lot of time in the long run. Operating without music theory while possible offers no real advantages. By understanding music theory you are better able to understand the workings of music itself. When I was a teen learning music my aural skills (ability to hear then play music) were poor. I started relatively late (teens are consider late starters) so music was like a foreign language to my ear. I found that by learning theory I was able to better understand what I was hearing and as a result my musical ear improved dramatically.
I really encourage any musician to learn music theory. There is a great site called FREE MUSIC THEORY WORKSHEETS which is a great place to start. I also recommend a book called BRIMHALLS 3 in 1 THEORY which can be purchased via the G4 GUITAR SHOP ONLINE. Perfect for the beginner.
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