Diminished chords are denoted with either 'dim' or 'o' in the chord symbol, eg. Cdim or Co. The 'o' is meant to be a little circle, representing the symmetry of the chord (but I can't find the character on my keyboard, so the letter 'o' will have to do in this article!). 

Basically, a diminished chord is a stack of minor 3rds. For those of you who have no idea what that means, you can work out a dim chord by starting at the root, counting up 3 semitones, playing that note, then count up another 3 semitones, and playing that note too. So for example,

Cdim = C Eb Gb

where each note is a minor 3rd (or 3 semitones) above the other. If we go up another 3 semitones and include that note as well, we get Cdim7 or Co7:

Cdim7 = C Eb Gb A

and counting up another 3 takes us back to the root, C. So we're back where we started from, hence the use of the circle in the chord symbol. When I mentioned symmetry earlier, what I mean is this. If you were to play Ebdim7, you'd go through the same process as above but starting on Eb. Counting up minor 3rds, you'd end up with:

Ebdim7 = Eb Gb A C

which are the same notes as in Cdim7, only in a different inversion. We can therefore conclude that Cdim7, Ebdim7, Gbdim7 and Adim7 can be played using the same 4 notes. This is great news, because it means you only have to learn one voicing and its inversions, and you've learnt the diminished chords in 4 keys. So to cover all 12 keys, you only need to learn 3 different diminished voicings, but I'll leave you to work the other two out =)

When are dim chords used? Very often, they're used to create a chromatic bassline or voicing - chromatic, as in stepping up or down by a semitone. For example,

Em7 Ebdim7 Dm7

The Ebdim7 provides a chromatic bassline from E through to D, while the notes in the three voicings also have a descending chromatic effect. Dim chords aren't always used in this way, but this is just one of the more common occurrences, hence it was worth a mention.

Just before I finish, you may also see the chord symbol Cø. This is a 'half diminished' chord. This contains a Cdim triad, but the 7th is the minor 7th of C instead, ie. C Eb Gb Bb. Cø can also be represented as Cm7b5.

Well, I hope that sheds some light on diminished chords. If anything is unclear, let me know, and I'll tweak the article.

Write a comment

Name:
Email:
Subject:
Comment: *

Help prevent spam - enter security code above:
 

Harlan Carpenter
Posts: 5

Re:
Reply #5 on : Mon November 22, 2010, 01:47:00

---

What leaves me completely astounded is the fact that of all the Claptons, McCartneys, and Santanas in the world, I would be the hick guitarist from Colorado--and the ONLY guitarist--who would stumble upon and exploit the technique described in the ONLY entries logged below on this site...!

Absolutely incredible...!
H. Carpenter

Anonymous
Posts: 5

Re:
Reply #4 on : Mon November 22, 2010, 01:43:19

---

What leaves me completely astounded is the fact that of all the Claptons, McCartneys, and Santanas in the world, I would be the hick guitarist from Colorado--and the ONLY guitarist--who would stumble upon and exploit the technique described in the ONLY entries logged below on this site...!

Absolutely incredible...!
H. Carpenter

Harlan Carpenter
Posts: 5

diminished chords in improvisation
Reply #3 on : Wed November 17, 2010, 03:07:22

---

What caught my attention above was the comment about the misconception that diminished chords can be used ONLY in progressive steps of minor third intervals. I have been using them for years on the guitar as an improvisation tool, often in chromatic situations that would be all but impossible on a keyboard. But they work equally well in full-tones, half-tones, and any scale intervals as well.

Harlan Carpenter
Posts: 5

last entry--diminished chords
Reply #2 on : Sat October 30, 2010, 03:37:47

---

O0-oo-oops..! I mis-spoke on my last entry. I meant that one note at a time of a diminished 7 chord could be played FLAT to create four separate and distinct, unrelated dominant 7 chords. Sorry for the confusion...!--H.C.

Harlan Carpenter
Posts: 5

diminished chords
Reply #1 on : Sat October 30, 2010, 03:30:32

---

New perspective: (1) Omit the root note from any dominant 7 chord, and see what happens: GBDF - G = B diminished triad. (2) Play the root note of any dominant 7 chord sharp, and what happens: GBDF, play G sharp = AbBDF, a full diminished 7 chord...! (3) Play any note of this AbBDF sharp, and see what happens: four separate, distinct, and apparently unrelated dominant 7 chords...! This is a performance and improvisation technique I discovered years ago (accidentally) and subsquently perfected. Since then I have used it so successfully that I have torpedoed a hundred jam sessions, and deflated a whole lot of over-inflated egoes of fellow musicians from time to time. I find it very effective on the guitar for creating polychords, chromatic progressions, etc. It is especially effective when mixing diminished chords and diminished triad fingerings with open strings, all the way up and down the neck. I also completely ignore old misconceptions, i.e., diminished chords or progressions can only be used in minor-third intervals. I utilize them freely, anytime I like the sound.--H.Carpenter