Everything Diminished

Everything Diminished

The diminished 7th chord is an extremely useful and cool sounding chord.  Some people call it the full diminished chord.  

It has a unique quality because it is comprised entirely of minor 3rds.  

This gives us the following chord tones:

1   b3   b5   bb7

Don't let the double flat 7 scare you.  While it is essentially a major 6th, we say bb7 to keep with the 1 3 5 7 structure that we use to create 7th chords.

Because of this symmetrical structure, any note in the chord could be the root.  

For example: C dim7 = Eb dim7 = Gb dim7 = Adim7

It is also important to note, that if any of the chord tones were to go down a half-step, that note would become the root of a dominant 7th chord.  

For example:  C dim7 -> B7

And of course, the inverse is also true.  

This means from any dominant 7th chord, if you raise the root one half-step, it becomes the root of a diminished 7th chord.

Because of this, the diminished 7th chord is extremely useful in creating drastic tension around dominant sounds.  

It really sounds great following a IV chord.  

Check out this progression:

I ma   III7   IV ma   #IV dim7

In the key of A:

A   C#7   D   D# dim7

As you can hear, the dim7 chord really performs a similar function to  a dominant chord, and really requires resolution.  

With a chord this strong, what scale could we play over it?  The answer is the dominant diminished scale.

The dominant diminished scale is a very wild scale that is very dissonant.  

It's scale degrees are as follows:

1   b2   b3   3   b5   5   6   b7

This scale is perfect over the diminished 7th chord, as well as, over any altered dominant chord.  The scale is actually quite similar to the altered scale, containing many of the possible alterations to a dominant chord, but has a little different sound because of the major 6th and lack of a 4th degree.  

Attached are the five patterns of the dominant diminished scale.

Practice this scale the same as you have every other scale we have learned, and practice playing it over the jam tracks below.  Experiment with the diminished 7th chord and try to incorporate it into some of your own progressions.  

The diminished sound is such a colorful sound and I implore you to try to harness it to really add some great tension to your playing.

Jam Tracks:

1.  "A" - Ima - III7 - IVma - #IVdim7 - Ima - bVI7 - IImi - V7alt

2.  "F" - Ima - III7 - IVma - #IVdim7 - Ima - bVI7 - IImi - V7alt

3.  "C" - Ima - III7 - IVma - #IVdim7 - Ima - bVI7 - IImi - V7alt