Classic Three Note Voicings

In my last post about variations on "All of Me", I used a series of classic 3-note rhythm guitar voicings. The voicings, using only 3 notes and mostly on the G, D, and low E strings, are the basic vocabulary for Swing rhythm guitar. While there is no "rule" against 4-note voicings or other variations, understand that these chords make up most Swing rhythm guitar for very practical reasons which we'll talk about now.

1. More notes would be redundant - With up to 13 horns in a big band, chances are that every note in a given chord is being covered somewhere. Of course, some of the notes will be doubled, but unnecessary doubled notes coming from the rhythm guitar will sound muddy and obscure the rhythmic punch and zing of your four beat pulse.
   
2. The Narrow "Window" - Again, with so many other musicians, there is a limited space in the frequency range for the rhythm guitar to poke through. There is small hole above the bass, but below the right hand of the piano, and this is exactly where those classic three note voicings come in handy. These voicings fit perfectly in that narrow range.
3. They are easy to finger - This especially true when you get up-tempo. Unlike a modern jazz setting where you can comp sporadically, swing rhythm guitar requires you to play quarter notes the whole time. Since you have to play every beat, why use complex, hard to finger chords?
   
4. You don't have to play as loud - It might seem unrealistic for a rhythm guitar to be heard amongst so many other instruments. But, if you stay within that frequency band I mentioned above, you don't have competition from other instruments in that range. Since you're not competing directly in that range, you can get by without having to play as loud. If you were to play higher, you'd be competing with the right hand of the piano - and you'd have to play over the piano to be heard. Lesson: Don't work so hard!
5. Lower Interval Clashes - Although a close cluster like E, G, B, C (Cmaj7) might sound good on the top strings of a guitar, or in the right hand of the piano. But small, dissonant intervals do not sound good in the lower registers. This is why the classic voicings are voiced on the low E, D and G strings. The space large space between the note on the low E and the D strings helps avoid the muddiness of the low register.

These are the reasons why the classic three note voicings work so well, and are therefore so prevalent. But of course, rules were meant to be broken, or at least bent. There are sometimes when the 3 note voicing is not practical, or just doesn't sound right. Here are some examples of bending the rules.

• Notes on the A string instead of the low E string: Take the example of the Am6->D7 change in "All of Me". The normal voicing for both chords would be A, F#, C on the E, D and G strings - yes, the same voicing with no change for both chords. Realize that the bass player has got the root covered, so the change will be heard. But, to me, it sounds so weird to hear the guitar not change - at least when I'm the one playing it. So, I often play a root on the A string instead.
  
• Awkward fingerings higher up the neck: Often times a Dm6 or Em6 chord at the 10th or 12th fret is a little awkward to finger on an acoustic. I'll often substitute the same chord (D, B, F) on the A, G, and B strings. Since it's the same exact notes as the lower string voicing, I don't worry about the range issue. Honestly, any of the minor chords between Dm and F#m are easiest to play with this voicing, and I'll rarely go out of my way to play the standard voicing.

Hope this helps to make some sense of the traditional 3-note rhythm guitar voicings.