Hey Friend,
I got another question about 7th chord progressions, this time from Michelle. She wanted to see the 7th chord harmonic progression in action.
I totally get that. To be able to visualize what you hear can be extremely powerfully in the learning process, especially when all the names look similar.
She also mentioned she has some confusion about the dominant 7 and diminished 7 chords.
First off, if you’re a Rocker, it is rare that you will ever see a diminished 7 chord. I would hazard to say that unless you’re a Jazz player, you’ll never have to play a diminished 7th chord (except in these lessons).
Dominant 7th chords, on the other hand, are used all the time in Rock, Blues, Pop and Country.
Get used to these. They’re easy to play and add a bit of twang to a major chord.
So what’s the difference between a dominant and diminished 7th chord?
A dominant 7th takes a regular major chord and adds the minor 7th note from the scale the chord is built off of. This is the note that gives that twanginess (like my new word?).
Notice the G7 chord in the exercise. If it was a G major chord, the fifth fret, fourth string would have a finger down, doubling the root note of the chord (G). By using the root note on the sixth string (G on the third fret), we can free up the G note on the fourth string to play the minor 7 note. That minor 7 note is F.
G major is made from using the 1 3 5 notes from the G major scale, so F# gets lowered a half step (one fret) to F.
G Major Scale
1 2 3 4 5 6 7 (8)
G A B C D E F# (G)
So a G7 chord uses notes G, B, D and F.
A diminished 7th chord is not based on a major chord - it’s based on a minor chord. It takes the minor form of a triad and then further lowers the fifth note from the scale to a flat 5 note.
You have the minor third and minor fifth notes added to the root note (tonic). Add the minor 7 note to this mix and it gives you the diminished 7th chord, which is the same as saying a minor 7th chord with a flat 5 note (ex: Bm7(b5)).
The example in the exercise is a B°7. Notice the root note B is on the sixth string, seventh fret. The flat 5 (F note) is on the fifth string, with a repeated root note B on the fourth. The 3 note is the D on the third string, and the minor 7 is Ab (A flat) on the second string. The notes are B, D, F and Ab.
B Minor Scale
1 2 3 4 5 6 7 (8)
B C# D E F# G A (B)
So the difference between a dominant 7th and diminished 7th is this in a nutshell: The dominant is based on a major chord plus a minor 7 note. A diminished 7th is based on a minor chord plus a minor 7th note. Does that make sense?
Here are the exercise files:
Alright, gotta roll. Have a good one, Rockers!
Peace~
Dave
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