Wes Montgomery - One of the few guitarists considered a musical genius for his ability to improvise by ear.
It's interesting that this musician had the ability to hear all the harmony and knew where to find the notes on the guitar without necessarily learning any scales.
I used to work with a lot of jazz guitarists and remember thinking how it often sounded like too much noodling around on the fingerboard - too many notes, too self indulgent. It's true, it is easy to get carried away by the harmonic possibilities in jazz and forget that making music is as much about the space you leave between the notes as the notes themselves.
Apart from Classical guitar, Jazz guitar is great study material for learning about chord harmony. Music is fundamentally about tension and release, or 'home' and 'away'.
If you take the time to analyse all the ways in which jazz manipulates this tension and release - the extremes to which it applies the tension and then disguises the release, you'll learn a great deal about music in general. If you've every looked into Altered Dominant chords or Chord Substitution you'll have some idea of what I mean.
Yes, that's a bit deep for an opening paragraph, but my point is this: Jazz isn't complicated - it just sounds like it is. All those complicated looking chords and scales boil down quite simply to 3 sounds - major, minor and dominant - or you could interpret them as optimistic, reflective and tense; after all, music is an expression of human emotion, not just notes and theory.
If you don't like jazz (yet), it might well be because you can't appreciate it's subtleties, or perhaps you've been put off it by negative association. But as a method to illustrate chord harmony and open up music theory to critical interrogation it's excellent. At the very least, it's a great way to learn about improvisation at any level.
Chords and Intervals
If you haven't yet learned chord harmony, this would be a good place to start finding out about chord-construction and intervals. Since there are only 3 types of chord it's easy to pick up.
All you need to know is a major scale in the key of C and to understand the difference between a tone and a semitone.
Try and find out which intervals from the major scale are used to create a major, minor and dominant chord. For example - what intervals do you need - minimum - to make a minor chord sound? What interval makes a dominant chord tense?
This simple exercise will teach you about minor and major 3rds, flattened (b)7th intervals and why 5ths are so popular in heavy metal. You'll also get into diads, triads and octaves and diatonic chord substitution.
If it all gets a bit much, give me a call.