Naming a Diminished Chord

[3shiftgtr]

You guys here are so generous. I am so glad I found this place.

I am a self taught player, and I need your help. Can you help me once and for all, get some questions on diminished chords/scales answered? Any help would be appreciated!

Do I have this correct?

Chords:

1,b3,b5 is a diminished triad. Also known as a diminished chord.
1, b3,b5,b7 is a half diminished chord, also known as a m7b5.
1,b3,b5,bb7 is a diminished 7 chord.

If these are correct, can anyone tell me why the m7b5 is called HALF diminished? Is it because the b7 isn't a m3rd away from the b5? And is the dim7 called as such cuz the bb7 IS a m3rd away from the b5? Or does that even have anything to do with it?

Next question is scale related.

The half-whole and the whole-half are the only two diminished scales, right? (super locrian, 7th mode of melodic minor doesn't count as the name diminished/whole tone scale is just a kind of slang, right?)
Half-whole 1,b2, b3, b4, b5, 5, 6, b7
Whole-half 1, 2, b3, 4, b5, b6, bb7, 7

And these can be used any number of ways, and they repeat themselves every minor third, right? I love their sound and use them alot in a lot of different ways.

But which chord goes with which scale? I use locrian over a diminished chord when it functions as a vii chord. But does the half-whole go with the dim 7 chord or the half dim?

My guess is that the whole-half goes with the dim7 cuz it has the bb7 in the scale, and the half-whole goes with the half dim cuz of the b7.

Am I in the ballpark, here? Are their any other diminished chord/scale functions that I need to know about?

I often used diminished as a spice rather than a straight chord/scale function. And if I zipping thru some changes, and I don't know which dim scale to use, I'll just work the triad and some neighbor tones. But I'd like to get a clearer view.

Thanks guys.

[bkdavidson]

You have the different diminished chords right. You answered your own question with the naming of the diminished and half-diminished chords. A dim. 7 or "fully dim." chord is called such because it is stacked minor thirds and is drawn from the diminished scale. Half-dim. chords are built from the locrian mode, and have a major 3rd as the last interval.

You have the two forms of dim. scales right. If you really wanted to be nitpicky and technical, the "5," "6," and "b7" in the half/whole scale would be called "bb6," "bb7," and "bb8." The "7" in the whole/half would be a "b8." In the real world this doesn't matter, no one on here will care, but your theory professor will dock you points. As for the uses of the scales, I'm not really sure. I may be a giant theory nerd, but I went through a classical program and not a jazz program, so I never really learned how to use diminished scales. Hope this helped.

[gingerjazz]

use the half/whole dim scale over dom7b9 chords and the whole/half over dim7 chords you can also use the half/whole dim over dom7chords mark levines book on jazz theory would be great for you if you really want to learn more about this stuff

[bako]

The diminished/whole tone naming of melodic minor is based on the 2 halves (tetrachords) the first diminished and the second whole tone.

1 b2 b3 3 (b4)-------------------b5 b6 b7 8


Build all the chords possible from any scale (collection of notes). In theory the scale is usable for any of these harmonies. However it may contain notes that are highly dissonant or contradict the harmonic function.
ex:
a major 3rd on a minor chord.
It still can be used with care as a passing tone.
When a major and minor 3rd come together the major function tends to win out and the minor 3rd is heard as #9, a good sound but no longer a minor chord.

Sometimes a scale might not contain all the prime notes of a chord but contain elements of harmonic function.
Ex.
Gb pentatonic on C7
Gb-----b5
Ab------b13
Bb-------b7
Db-------b9
Eb--------#9

In a band situation the harmony is formed by the sum total of all the notes played.
Playing solo the super imposition is heard best when the context is stated or at least when the upper function notes resolve to the chord you are aiming for.

What notes can’t be played against a particular chord?
Can those notes be tied in with a dominant of that chord or another related progressional function? On some level all 12 notes are available for use at any time when you can hear and understand the relationships. Style, context and personal preference are the determining factors of when to use what. Modal/scale – chord relationships provide a helpful snapshot view that highlights a few intervallic relations at a time (a more manageable chromatic scale).

[epiemperor]

For what it's worth, a diminished seventh chord contains two diminished intervals measured from the root (a diminished 5th and a diminished 7th), whereas a half-diminished seventh chord contains one diminished interval measured from the root (a diminished 5th). Therefore, it contains only half as many diminished intervals as the fully diminished seventh chord.

[Reg]

The three common sources of dim chords are, 7th degree of Harmonic min, 7th degree of Harmonic Maj. and of course symmetrical dim.. ( you have the two versions of symmetrical scales)
Dim chord usually fall into one of three patterns;
1) ascending, root resolves upward by 1/2 step, and usually have dom. function.( can be derived from secondary dominant of their target chord. (C#dim7 derived from A7b9), Har. Min. or Har. Maj.
2) Descending; root motion resolves downward by 1/2 step, not usually dominant function, but chromatic function. Chord tones do not suggest Sec. Dom. of target chord. Symmetrical.
3) Auxiliary; usually the root of dim. chord is same as root of chord of resolution. Mostly I and V of key area. Also usually Symm.
A lot of players use the two tri-tones of dim chords to create a organized system of resolution. It's been around for years and our ears are use to the sound. A little to synthetic for me, but I still hear great players using it all the time. This is somewhat the basics of Dim. harmony and I'm writing from memory... I'll try and write out the mechanics, to clear the cob-webs from head, just finished three hour outdoor solo gig... I dig playing them but take a lot of energy... best Reg

[jimbopper]

I know of two options on the half diminished chord. First the major scale from whence the chord came, so B half diminished comes from the C major scale as the seventh chord in the scale right?

The other option would be D melodic minor. B half diminished's notes also fit in that scale.

If you are super hip you could play D melodic minor of B half diminished, and since it is normally followed by E7alt you could move up a minor third for the E7alt chord and play F melodic minor.

[BigDaddyLoveHandles]

I know of two options on the half diminished chord. First the major scale from whence the chord came, so B half diminished comes from the C major scale as the seventh chord in the scale right?

The other option would be D melodic minor. B half diminished's notes also fit in that scale.

I'm lazy. For m7b5 chords I think of them as dom 9th chords w/o root: B-D-F-A is G-B-D-F-A minus G. Your two suggestions fall out of that:

1. Playing C major scale over Bm7b5 is playing C major (= G mixolydian) over Gdom.

2. Playing D jazz minor (D E F G A B C# D) over Bm7b5 is playing D jazz minor (= G lydian dominant) over Gdom.

Note: that just as Cnat is an "avoid" tone over G7, so Cnat is an avoid tone over Bm7b5; that's why the C# sounds good over both.

[M-ster]

use the half/whole dim scale over dom7b9 chords and the whole/half over dim7 chords ...

Simplicity is elegance, and gingerjazz' answer strikes me as most succinct.

The "half diminished" is slang or shorthand for m7b5. You've got all that worked out in your original post, except for dismissing "half diminished."

Three more thoughts:

1) dim7 voicings are often substitutes for dominant 7(b9) chords. That's how you arrive at using harmonic minor scales with them.

2) Thinking whole/half over a dim7: You can add any note a whole step above any dim7 chord-tone as a tension. This usually gives you a hipper voicing than the stock dim7 provides.

3) Even when you're using a dim7 as a 7b9 voicing, item 2 still applies.

[ChuckAndersonGuitar]

The half diminished 7th chord refers to the fact that the 7th is halfway between the maj7 interval and the diminishd 7 interval. There are 3 species of 4 part diminished type chords: dim(maj7), half diminished 7 and diminished 7. Formula for each: 1 b3 b5 7 1, b3, b5, b7 1 b3 b5 bb7

The half diminished 7 and the m7b5 are not interchangeable terms. They do have the same notes but their implied applications are different. The half diminished 7th is derived from a diminished chord - the m7b5 is an alteration of a m7 chord. Most famous examples are the II chord of a minor key - the m7b5 and the VII chord of a major key - half diminished 7th.

[ksjazzguitar]

The half diminished 7th chord refers to the fact that the 7th is halfway between the maj7 interval and the diminishd 7 interval.

That explanation of the origin of "half" seems fishy to me. When these chords were being used, the dimMaj7 is a chord that wasn't used. I don't know how long the term half-diminished has been in use, but I'm willing to bet it predates the common usage of dimMaj7s. It may be a handy tool to teaching it, but it sounds like a retroactive explanation to me. Do you have a source for this? Just curious. I'd been taught it was called "half" because it wasn't "fully" diminished - only the triad was diminished and not the 7th.

The half diminished 7th is derived from a diminished chord - the m7b5 is an alteration of a m7 chord.

I wouldn't say that "the m7b5 is an alteration of a m7 chord." It is derived from the harmonization of the second scale degree of the minor scale which was previously referred to as a half-diminished in the classical world. It is not an alteration of anything but is naturally occurring in the scale as-is. I suspect that jazz musicians chose to refer to it as "m7b5" because they are so used to thinking Major ii-V-I where the ii7 chord is m7. So I would agree that the name probably comes from jazz musicians thinking of it as an altered m7, but that's not really the same as derivation of the chord itself.

Peace,
Kevin

[M-ster]

... I'd been taught it was called "half" because it wasn't "fully" diminished - only the triad was diminished and not the 7th.

Ditto ...

The half diminished 7 and the m7b5 are not interchangeable terms. They do have the same notes but their implied applications are different. The half diminished 7th is derived from a diminished chord - the m7b5 is an alteration of a m7 chord. Most famous examples are the II chord of a minor key - the m7b5 and the VII chord of a major key - half diminished 7th.

This is the first time I've heard anyone assert this, and it sounds questionable, to me. Both of your "famous examples" are naturally occuring (diatonic) tertian harmony - neither is an alteration. Nor do I see any point in viewing or teaching them as two different things.

[gingerjazz]

I agree with Kevin on this one the explanation would seem to be in the chord name as with so many jazz chords.Half diminished surely would seem to suggest that it is half way to being a fully diminished chord.Seems like common sense to me.Now i am only working towards my grade four music theory at the moment and so would be happy to be corrected if im wrong.

[FatJeff]

Well, that's the way I learned it, too...half diminished because the lower triad is diminished, but the upper triad is minor. In a fully diminished seventh chord, both triads are diminished.

[KShri]

The half diminished 7 and the m7b5 are not interchangeable terms. They do have the same notes but their implied applications are different. The half diminished 7th is derived from a diminished chord - the m7b5 is an alteration of a m7 chord. Most famous examples are the II chord of a minor key - the m7b5 and the VII chord of a major key - half diminished 7th.

They are definitely interchangeable terms.

There are no naturally occurring II chords in a minor key or VII in major key. Please be careful here, this is pretty much like math, it's either right or wrong. There is a ii dim chord occurring in a natural minor scale and a vii diminished chord in a major scale.

[ksjazzguitar]

There are no naturally occurring II chords in a minor key or VII in major key.

Are you saying that these chords are not major? Just trying to clarify. If that's what you mean then I agree.

Please be careful here, this is math, it's either right or wrong. There is a ii chord occurring in a natural minor scale and a vii diminished chord in a major scale.

I assume that you mean that the "ii chord occurring in a natural minor scale" is diminished.

Yes, it is math and the harmonization of the scale (based on the a priori assumption of how scales harmonize) is mathematical. But the decision of how to label them is completely arbitrary. Whether they called half-diminished or m7b5 or elephant-peanut-butter-dishwasher chords is completely arbitrary - it's just labeling. Classical has one convention and jazz has another. But we shouldn't fool ourselves into thinking that these aren't based on a tradition that at one point was arbitrary. I wouldn't say that that they are "interchangeable," but that they are the same chord that is being referred to with different labels by the different traditions (presumably because of different use.)

Peace,
Kevin

[rwmol]

I'm a bit unclear on this. Let's say I'm writing a score in three flats (Eb). I want to enter a passing chord of F-B-D-Ab between G7 and Cmi7. What is the theoretical way to name this chord?

Thanks

[pkirk]

what's wrong with Fdim?

[rwmol]

what's wrong with Fdim?

I'm not sure. Are you saying I can make it Fdim7, Cbdim7, Ddim7 or Abdim7 and they are all OK?

[bako]

Leading tone diminished chords are named in reference to the chord they are approaching.
Bdim (B D F Ab) > Cm

[JonR]

Leading tone diminished chords are named in reference to the chord they are approaching.
Bdim (B D F Ab) > Cm

This.
Even when the bass note is F, Bdim7 (I like to see the "7" personally) would be the correct name if going to Cm (or C).
However, "Fdim7" would hardly be misunderstood in context, or cause too many raised eyebrows...
Especially if you want the bass note to be F. "Bdim7/F" would look too fussy, IMO.

[logictweek]

I like the Bdim7, leading-tone explanation. Also, if I saw that progression on a chart, I would be thinking of it as G7b9 rootless. And if it were a half-diminished I would think of it as a G9 rootless.

[jasaco]

I think it's a legit question, especially when you consider what note you'd wish the bassist to play. (Or would you never care which of the 4 pitches the bass played? I guess often the passing chord will be for just one beat so maybe it's over before anyone realizes it anyway and the bass note doesn't matter much?)

[Flyin' Brian]

We have an original that has the bridge written in this way simply because of what we want the bassist to play. The song is in Am, 4/4 and the changes are one measure each with the bassist playing whole notes.

Cm7 - Bdim - Am - Adim - Bm - Cdim - Bm - E7#5b9

[rkettner]

Leading tone diminished chords are named in reference to the chord they are approaching.
Bdim (B D F Ab) > Cm

Diminished chords are symmetrical, made up of consecutive stacked minor thirds, so each chord tone is a diminished chord. If you had this conversation with a classical musician, they would probably correct you for calling it a D or Ab or F diminished. However, for all practical purposes, you could think of it that way. You can also think of the Ab as a G7 chord with a b9th.