STUDENT: I feel that songs with simple major chord structures (i.e. 1 4 5) are more limiting in what notes and chord extensions you can improvise with vs structures with say minors, maj7, dom7. Your thoughts?
PAUL: It depends on how we view chords. All of the chords mentioned (1 4 5) are in a single chordal family: the Major chord (with or without extended intervals). The only difference between the Minor and its options is that we have to honor its basic interval formula (1 b3 5), whereas for all of the Major chords you mentioned we would have to honor the 1 3 5 formula.
Notes that exist in the chord are called Chord Tones. A C Major triad has three chord tones, the 1 3 5. A Cdom7 has 4 chord tones, the 1 3 5 b7.
By “honor” I mean “rest or pause”. I focus mainly on those chord tone intervals as I improvise. As to application, I can approach any 1 4 5 song diatonically, which I do all the time. Each diatonic option gives me all of the unaltered extensions, otherwise known as the Harmonized Major Scale. Here are intervals I get by using Group 1 for my example in the key of C:
C D E F G A B C D E F G A
1 2 3 4 5 6 7 8 9 11 13
From John Hughey to Lloyd Green to Buddy Emmons and all the rest, many of their signature licks used all of these Harmonized Major Scale structures/intervals over a single "1" chord.
Here are the intervals derived from the Harmonized Major Scale chords that made the 60’s steel guitar styles famous.
Using Group 1 throughout, the intervals from the parent Major Scale are:
C = 5 1 3 Dm = 6 2 4 Em = 7 3 5 Fmaj = 8 4 6 Gmaj = 9 5 7 Am = 3 6 8 Bdim = 11 7 9
Remember: 8 is the root an octave above the root. The 9th is a 2nd an octave above the root, the 13th is a 6th, 11th is the 4th. (Subtract 7 from any number 8 or higher to get the basic interval). Intervals 2 4 6 = 9 11 13.
When a dominant 7th is played in a 1 4 5 progression I am free to alter the 5 chord’s 9ths and 11ths over the C7. The C7 formula is 1 3 5 b7. When I hear it in a song, that tells me the chord needs resolving. I can choose to play emphasizing the pure 5th, 6th, 9th, and 11ths or I can choose voice leading tones by altering those same intervals, such as b5, #5, b9, #9, or #11.
This is why we also must listen to a lot of different musicians and different musical genres. What we learn to love as listeners will also become a deciding factor in intervals we decide to emphasize.
The only rule is this: When we rest or pause, it always sounds great and correct to pause on one of the "sweet" intervals within the basic structure. Use your ears to determine which intervals sound best over any given diatonic chord.
Otherwise, all intervals in the Harmonized Scale are usable as notes to weave in and out of.