Watch the Breakdown 1 online guitar lesson by Andy Aledort from Slow Blues Power
One of the great things about soloing over dominant seventh chords—and something that is certainly an essential technique when improvising on a slow blues—is that players are free to exploit the difference in quality between the minor third and the major third. The scale most closely associated with dominant seventh chords is Mixolydian; in G, G Mixolydian is spelled G A B C D E F, with B as the major third. The minor third is one half step lower, Bb; this pitch can also be thought of as the b9 (“flatted ninth”).
In bar 1 of the solo, I begin on beat one by hammering on from the minor to the major third, and, on beat two, incorporate both the minor and the major third. Be aware of the difference in quality between these intervals and try to take advantage of that difference while crafting your solos.