EMU professor and friend of the magazine Mark Whetzel shares his scholarly take of applied guitar harmony in jazz and shell voicing basics.
For the guitarist who is interested in jazz harmony, shell voicings present an excellent opportunity to learn new chords while providing a convenient way to categorize them.
Though it sounds complex, the theory is reasonably easy, if you know intervals.
If you're not familiar with intervals, I'd recommend a crash course as a precursor to this article:
- How to Play Guitar Primer Article
- The Complete Intervals Lesson
- Intervals Lesson Outline and Cheat Sheet [PDF]
Now, some shell voicing basics:
Simply put, shell voicings contain the essential notes of any chord (a root, a third and a seventh) while usually providing plenty of options to add extensions (ninth, 11th and 13th).
Let's start by taking three of the more common shell voicings and examine how we can use them to create more interesting harmonies.
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Jazz Shell Voicing Chord Progression in F
Notice that none of these contain the fifth of the chord.
Only the root, third and seventh are present.
Of the four notes in a seventh chord, the fifth provides the least amount of harmonic information. It doesn't give us a reference point (like the root) or tell us if the chord is major or minor (like the third).
It also does not tell us if the chord contains a dominant seventh or a major seventh.
However the fifth can be added later if you choose too. It is also frequently altered (♯5 or ♭5).
Building harmony without extensions
You'll also notice that even without extensions (ninth, 11th and 13th) the harmony is clearly laid out with these basic shell voicings.
This is primarily because of the third and seventh of each chord.
These notes are sometimes referred to as guide tones. Notice how much chromatic movement is involved as the 3rd's and 7th's of the chords flow into one another.
Here's another example using a similar progression, this time in the key of C:
This provides smoother voice leading.
Another thing to note is that these voicings have their root on either the fifth or sixth string just like the basic barre chords that we're all familiar with.
It's certainly possible to play shell voicings with the root on the fourth string too. However, for now we'll keep the root on the lower two strings. This also allows us to add more extensions which we'll look at later.
Now let's add a “G” note on the second string to the chords in our first diagram and see how it changes the progression:
Adding a G to the second string
Over the F7 chord, the addition of the “G” note gives us an F9.
The B♭7 becomes a B♭13 and it simply adds a fifth to the C7 chord. The chords sound even more connected to one another when the same note occurs in the top of each one in the progression.
Before looking at other extensions, we'll look at some additional shell voicings that provide more harmonic interest to a basic blues progression:
Voice Leading in a Basic Blues Progression
In this example, these basic three note chords create a lot of harmonic movement.
Pay particular attention to the two new voicings, F♯m7 and Am7. The F♯m7 in bar four is the same fingering (different fret) as the F7.
The third of the chord has been lowered one half step which makes it a minor seventh.
Likewise, the Am7 chord in bar 11 is similar to the voicing that we used initially for B♭7 and C7.
Again, the third has been lowered to make it a minor seventh chord. For serious jazz students, you'll notice that these voicings sound a bit like those used by Count Basie's legendary rhythm guitarist, Freddie Green.
Once again, let's add a note to the 2nd string and see how it changes the chords and underlying harmony:
Expanding harmony in the blues progression
Refer to our earlier example where we added the “G” note to the second string.
Remember this functioned as either the ninth, fifth or 13th of the chord.
Likewise we'll add or modify the ninth, 13th or fifth in most of these new chords. Analyze the new chords to see how the second string changes the name of the chord.
The three chords that might require some explanation occur in measures 11 and 12 of the above progression.
The Am11 has a “D” on the second string. This is the fourth note of an A minor scale which is often referred to as the 11 when voicing chords. The A♭7♭5 is easy to understand. We're simply lowering the fifth of the chord by one fret thus making it a ♭5.
The C7♭9 has a “D♭” note on the second string. When compared to the other 9th voicings, we see that this note has also been lowered one fret.
Let's use another common jazz progression to look at some more dissonant voicings. We'll use the first couple bars of Gershwin's “I've Got Rhythm” which is more commonly referred to as just “Rhythm Changes.”
Example from Gershwin's "Rhythm Changes"
The only new shell voicing we need for this example is the Cmaj7 with the root on the fifth string. Again, this consists of the first, third and seventh of a Cmaj7 chord.
Just like we did in the blues example, we'll now add some notes on the second string.
These simple additions create a lot of harmonic interest. We'll also add a “D” to the Cmaj7 shell voicing creating a Cmaj9. This gives us a chromatic line in the top voice which descends nicely.
Chord naming conventions explained
Here is something for those of you who enjoy the theoretical aspect of all of this.
The alterations to the dominant seventh chords in this example provide an opportunity to address a common question I get asked in lessons concerning the correct way to name a chord.
Notice that I labeled these chords as A7♯5 and G7♯5 respectively.
I did this because it's easy to understand this alteration since it relates specifically to a note in the chord (the fifth). However, these chords could also be called G7♭13 and A7♭13. Technically, there's a difference between, for example, G7♯5 and G7♭13. Specifically the G7♭13 would still have a natural fifth (D).
This would occur if the chord were looked at as being the fifth degree of C harmonic or melodic minor ascending (sometimes called Jazz Minor).
But these chords, G7♯5 and G7♭13, are often voiced the same because of the logistics and limitations of the guitar. This difference in naming the chord may apply more to the soloist than the accompanist because it would affect the scale choice the soloist may use.
A Dissonant Voice Leading Example
We'll examine one more example which creates a lot of dissonance by incorporating extensions on the first string.
Look closely at the lowest three notes of the C6/9 and Cmaj13.
Those notes are C, E and A. This is actually a new shell voicing called a C6 which we use to build more colorful chords. They are the same shell voicing but have their roots on different strings.
The dominant chords (A7♭13♭9 and G7♯5♯9) are really dissonant. But notice how they flow nicely into the chords that follow (Dm9 and Cmaj13).
This sense of tension and resolution is something that really drew me to jazz initially. With some experience you'll be able to use some discretion regarding when to really push the envelope harmonically and when to be a bit more conservative.
Listening to great players will give you some insight into this.
Blues Shell Voicing Example in G
Finally, I've included 2 examples of a blues in G.
Shell voicings are a great place for guitarists to start when studying jazz harmony; however, they're ultimately most effective when incorporated with other approaches.
In these examples you'll find chords without roots, diminished chords, some quartal harmony and even some chords built on shell voicings that we didn't cover (like the E7♯9 “Hendrix” chord).
Learning by Rote
Just a few more thoughts concerning these chords.
First, I didn't have the fretboard knowledge to understand these chords when I initially learned them. I simply liked the sound of them. I'm a big fan of learning things by rote.
This really helps to develop the muscle memory required play these chords.
When your theory knowledge improves, I would suggest gradually learning how each note functions in a given chord. Also, if you find some of the fingerings difficult, approach them slowly.
It might take some time to develop the flexibility and stretching ability required to play some of these voicings.
Lastly, listen for these chords in other types of music besides jazz.
It doesn't matter if you're a Steely Dan or Stevie Ray Vaughan fan, you'll hear these voicings showing up in a variety of music.
Have thoughts or questions about the material covered here?
Feel free to chime in via the comments section below and we'll respond accordingly.
Flickr Commons Image via Omanaco