# Diminished vs half diminished question

Discussion in 'General Instruction [BG]' started by ryco, Oct 9, 2005.

1. ### ryco

Apr 24, 2005
97465
Can someone explain the function of a fully diminished chord/scale. And where does a full diminished chord occur naturally? It's got that funky old-timey sound to it but I hardly ever hear it used anymore. How does it resolve?

Full dim: R, M2, m3, P4, d5, bb7, (M7)

Half diminished occurs all over the place (vii in Ionian) and functions as a substitute for V (V9 without the root) a lot. Used as a substitute for minor chords sometimes; ex m9b5

Half dim: R, m2, m3, P4, d5. m6, m7

2. ### Wrong RobotGuest

Apr 8, 2002
Well, Diminished harmony is a huge can of worms. I don't actually have that much time to get into it, but the thing about the diminished scale is that it's symmetrical. Typically you see what is referred to as the half-whole diminished scale. Starting on C, this scale is constructed like this:

C-Db-Eb-E-Gb-G-A-Bb-c

you will notice there are 8 tones in that scale, this makes it a little different from major/minor harmony. Also, due to being symmetrical. There are actually only 3 half-whole diminished scales.

Db(also E, G, Bb), D(also F, Ab, B) and Eb(also Gb, A, C)

Um, that's all I have time for now, perhaps some other theory goon will fill in what I left out.

There is also a whole-step half-step diminished scale, but um...yea... later, sorry.

May 4, 2001
Eugene, OR

This is GI all over again...

4. ### Wrong RobotGuest

Apr 8, 2002
Right so anyway. The diminished chord is typically not seen all too often, though historically it has been used often to either bridge sections, modulation, or to create a sense of atonality, disambiguate the root or tonal center.

You don't see it too often in jazz, where the half-diminished is fairly common(being locrian, vii of ionian..etc.), but you do get a lot of diminished harmony in modern classical(eh..) newmusic...etc.

I personally use diminished harmony a lot when improvising in minor tonalities. The diminished scale, being 8 notes and fairly out of key with major/minor scales, has a great melodic quality to it that I really dig. But it's just one of those things, I trust my ears with.

Um, again, diminished harmony is a can of worms, hopefully some more knowledgeable cats'll come along and fill in the blanks.

5. ### emjazzSupporting Member

Feb 23, 2003
Bronx, NY
Hey Wrong Robot, if you like the sound of diminished lines than you owe it to yourself to get the Slonimsky book. It's called the "Thesaurus of Scales and Melodic Patterns" by Nicolas Slonimsky. This is the book that Coltrane used to practice out of. It's also what Allan Holdsworth uses.

6. ### Mike Dimin

Dec 11, 1999
The diminsihed chord is often used as a passing chord between 2 chords. The diminshed 7th chord also has 2 tritones (R-5th and 3rd to 7th) allowing it to substitute for 2 different dominant 7th chords.

Mike

7. ### Richard Lindsey

Mar 25, 2000
SF Bay Area
Actually, allowing for enharmonic equivalences, it can substitute for four different dominant 7ths. Bdim7 can function as G7b9 w/o the root, E7b9 w/o the root (= G#dim7), Bb7b9 w/o the root (= Ddim7), or Db7b9 w/o the root (= Fdim7).

8. ### Mike Dimin

Dec 11, 1999
Absolutley - I don't know what I was thinking

Mike

9. ### Richard Lindsey

Mar 25, 2000
SF Bay Area
I believe that would be C-Db-Eb-E-Gb-G-A-Bb-C, no?

The whole-half variant would be C-D-Eb-F-Gb-Ab-A-B-C.

Both scales contain the chord tones C-Eb-Gb-A.

10. ### Wrong RobotGuest

Apr 8, 2002
Ya, you know, the brain, it does funny things sometimes, I actually originally had written it out with sharps, but it looked funny, so I backtracked over it with flats, you know, we all make mistakes.

11. ### PacmanLayin' Down TimeStaff MemberGold Supporting Member

Apr 1, 2000
Endorsing Artist: Roscoe Guitars, DR Strings, Aguilar Amplification

Just for clarity's sake, the half-diminished chord most often functions as a ii chord in a minor key (Dm7b5 - G7b9 - Cm7), not as vii of a major I.

Hope I'm not being too nit-picky....

12. ### emjazzSupporting Member

Feb 23, 2003
Bronx, NY
Good catch.

I do have a question though. I'm going over Ornithology in the omnibook and there's a change in it where the A half-diminished goes to D7 and then to G. Why would this be done? It only happens once and it's during the solo. Maybe this isn't enough info......any thoughts?

13. ### Mike Dimin

Dec 11, 1999
Often times the minor ii-v doesn't resolve as expected, or for that matter the major ii-v doesn't. An example would be How High The Moon: A-7/D7/G-7 then A-7b5/D7(b9)/ Gmaj7. It's a bit of a decptive cadence - in your case, setting up the G minor and then resololving to G major

Mike

14. ### Mike Dimin

Dec 11, 1999
Additionally, the locrian mode is not usually played over ii-7(b5). You will often find the Locrian #2 which comes from the 6th degree of the Melodic Minor Scale

Mike

15. ### Wrong RobotGuest

Apr 8, 2002

Ya, I was aware of this. But good for throwing it out there anyway.

16. ### Wrong RobotGuest

Apr 8, 2002

And as for the WHY? because anything that catches you off guard is hip!

17. ### emjazzSupporting Member

Feb 23, 2003
Bronx, NY
Thanks Mike! Actually, I was told to look at How Hight the Moon because it's the same as Ornithology.

18. ### emjazzSupporting Member

Feb 23, 2003
Bronx, NY
Yay Melodic Minor!!!!!

19. ### geoffkhan

Yes, this is correct. Good catch.

20. ### RhythmBassist01

Aug 31, 2005
Diminished and Augmented chords are Dissonant, and Major and Minor chords are Consonant.

You can use diminished chords to modulate as well.