So, what the heck is a shell voicing, you ask? That's a term from jazz arranging, also used by jazz pianists, that refers to the basic essential notes of a chord. You ever hear a piano solo whare the guy snaps out those cool 2 and 3-note chords in his left hand that sound so full? Wanna learn how to do it on guitar? Well, here goes:
First, we need to know what the essential notes of a chord are. They are (in descending order of importance) the 3rd, 7th, added tones, root, fifth. In English, that means in, say, a C13 chord, the most important notes are: E, Bb, A, C, G, in that order. What is implied is that you can omit the least important notes if you don't want them. Usually, the fifth is the first to go. Then the root - especially if you have a bass player. What would you need with another root? With that in mind, let's look at some guitar shell voicings for various chords.
These are just a few voicings. With this concept in mind, you can construct shell voicings over just about any chord you can think of. Try it!