Diminished 7
The diminished 7 chord (also written as dim7 or o7) is made up of minor thirds: root, minor third, diminished fifth, and diminished seventh.
The diminished seventh interval is the enharmonic equivalent of the sixth (B double-flat is the same as A). We'll be looking at the diminished 7 chord voicing from the foundation provided by all of our work on dominant 7 voicings.
Drop-3 Diminished 7
Dominant 9 Voicings: Another Use for min7(b5)
Minor 7(5) and dominant 7 chords have an interesting relationship. Take a look at these two chords, presented in close position.
If you were to put a Bunderneath a Dmin7(5), you would have the same notes exactly. Guitarists make good use of this.
Playing the min7(5) chord from the third of a dominant 7 chord yields a dominant 9 sound—you’re letting the bass player play the root for you. It is possible to wrap your thumb around to play the root as well, but this is easier for guitarists with larger hands to accomplish.
Dmin7(5) as a drop-2, from the fifth string up, related to B9 chord.
Dominant 13 Voicings and Chord Tensions
Well worth memorizing, here is a set of rules for adding color to basic seventh-chord shapes. If you are interested in making the basic voicings we've been working on for several weeks now to sound much richer, examine the following rules very closely. These rules make it possible to generate many more voicings from chords that we already know
We'll be working with application of these rules for the rest of the course. It's a way to take all of the drop-2 and drop-3 voicings that we know and change them into different voicings.
Let’s work with 6 replaces 5 first, replacing the fifth of the chord with the sixth. Here’s a B7 drop-3 voicing, with the fifth on the second string. Since “6 replaces 5,” in the second bar, the F is gone, replaced by a G. We now have a B13 chord, created from the B7 voicing.
Question: Why is the G called 13 and not 6?
Although enharmonically the 6 of the key of B, the G would be called the 13, since, when stacking notes in thirds, the G would occur above the 7. See the following:
In general practice, with seventh chords of any quality, tensions (notes other than Root, 3, 5, and 7) are listed as numbers higher than 7 (meaning 9 instead of 2, 11 instead of 4, or 13 instead of 6).
Replacing the fifth of the chord with the 13 on a drop-3 E7 on the sixth fret would look like this.
Diatonic Chord Exercise
We have practiced voicings moving up in half-steps, using Cycle 4 as well as tune progressions. Another way to drill and practice harmonic material is to play chords diatonic to a particular key. Remember, "All things in one key, one thing in all keys." We are going to stick to a single key and follow the chords up the diatonic scale.
First, let's tackle F major in drop-3 from the sixth string. The first chord is Fmaj7. To get to the second chord, we move each chord tone up a diatonic second, (F to G, E to F, A to B, and C to D) resulting in a drop-3 voicing for Gmin7. We're going to play all of the diatonic chords for the key of F.
The seven pitches of any diatonic scale can be obtained using a chain of six perfect fifths. For instance, the seven natural pitches which form the C-major scale can be obtained from a stack of perfect fifths starting from F:
- F—C—G—D—A—E—B
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