Watch the Duane Allman Style 3: Open E online guitar lesson by TrueFire from Blues Guitar Greatest Hits Vol. 1
Lesson Source: Andy Aledort's Slide Guitar Power
For all of the soloing on this track in the key of C, I alternate between lines played in eighth position (moving primarily between sixth and eighth positions) and quickly shifting up an octave higher to 20th position, where I move between 18th and 20th frets for the majority of the lines. Throughout the solo (and regardless of the fretboard position), remember to anchor the fret - hand thumb on the back of the neck in order to produce a string and stable vibrato. I prefer slow, wide vibratos in the style of Robert Nighthawk, but I encourage you to try vibratos of different width and speed. While playing up to the 20th fret and beyond, I bring the thumb in front of the neck, which allows greater range of motion, especially if I choose to move beyond the fretboard and over the pickup for some very high notes, as Duane would so often do.