What's the difference between a diminished chord and a diminished 7th chord?

[lkmuller]

I understand that there is a difference but there seem to be many opinions on this. I'd like some input please. Thanks!

[rpguitar]

A seventh.

A diminished chord is technically a triad: Root, m3, d5.
A diminished seventh chord is four notes: Root, m3, d5, d7 (half step below a m7)

(Just like a Major chord compared to a Maj7, or a minor chord compared to a min7.)

[lkmuller]

I've read that diminished 7th chords are actually min7b5 chords. I had never heard that before and wondered if any of you had ever heard that? And thanks for the reply, RP.

[rpguitar]

Not quite... But close: A m7b5 is also called a half-diminished seventh chord. That's probably what you've heard. There's one note difference between the two.

dim7:
Root, m3, d5, d7

m7b5 (half dim7):
Root, m3, d5, m7

[JonR]

I've read that diminished 7th chords are actually min7b5 chords. I had never heard that before and wondered if any of you had ever heard that? And thanks for the reply, RP.

Just to expand on rpguitar's answer:

Both chords are known as "leading tone 7ths", because they are built on the VII degree of major and harmonic minor, respectively.

m7b5, aka half-diminished = 1 m3 d5 m7 = vii chord in major key, but normally used as ii chord in minor key.
Eg, Bm7b5 (B-D-F-A) -> E7(b9) -> Am
Chord symbol: Ø

dim7, aka full diminished, but often abbreviated to plain "dim" (because dim triads are so rare in practice) = 1 m3 d5 d7 = vii chord in minor key (from harmonic minor). Always resolves to tonic, eg:
Bdim7 (B-D-F-Ab) -> Cm.
Chord symbol: °7, sometimes just °

Bdim7 can also be seen as a rootless G7b9 (V of Cm), same function.

Because dim7s are symmetrical, any one of them can resolve in 4 different directions (and therefore sub for 4 different dom7s), although strictly they need to be spelled differently:

G#dim7 = G#-B-D-F = vii in Am; rootless E7b9; resolves to Am (or A major)
Ddim7 = D F Ab Cb = vii in Eb minor; rootless Bb7b9; resolves to Ebm (or Eb major)
E#dim7 = E# G# B D = vii in F# minor; rootless C#7b9; resolves to F#m (or F# major). If used as vii in Gb major, should be spelled as Fdim7: F Ab Cb Ebb.

Of course all 3 dim7s sound identical to Bdim7, and spelling (at least in jazz) doesn't matter much; it just helps to reveal the derivation. (The usual improv scale is the equally symmetrical WH dim scale, not the vii mode of harmonic minor the chord comes from.)

[lkmuller]

Thanks RP and JonR for clearing that up for me. Aloha.

[Patrick2]

Not quite... But close: A m7b5 is also called a half-diminished seventh chord. That's probably what you've heard. There's one note difference between the two.

dim7:
Root, m3, d5, d7

m7b5 (half dim7):
Root, m3, d5, m7

Actually, a great way for the OP to hear the differences is to chord a CMaj7 chord at the 1st fret and then just run through what an old jazz instructor I once studied with (Al Faraldi) used to refer to a "The Five Qualities"

CMaj7 - C7 - Cm7 - Cm7b5 - (half diminished, but the Berkely grads hate that term) - Cdim

--x----- --x------- --x------- --x------- --x-------
--1----- --1------- --1------- --1------- --1-------
--4----- --3------- --3------- --3------- --2-------
--2----- --2------- --1------- --1------- --1-------
--x----- --x------- --x------- --x------- --x-------
--3----- --3------- --3------- --2------- --2-------

You can hear the intervals "walking" down . . . . and it can sometimes sound pretty good when used in a comp'g motif

edit . . . forgot to mention, it can obviously be done in any position and can be done without ever coming off the root.

flat the 7th, flat the 3rd, flat the 5th, flat the 7th (now m7) again

[JonR]

Actually, a great way for the OP to hear the differences is to chord a CMaj7 chord at the 1st fret and then just run through what an old jazz instructor I once studied with (Al Faraldi) used to refer to a "The Five Qualities"

CMaj7 - C7 - Cm7 - Cm7b5 - (half diminished, but the Berkely grads hate that term) - Cdim

--x----- --x------- --x------- --x------- --x-------
--1----- --1------- --1------- --1------- --1-------
--4----- --3------- --3------- --3------- --2-------
--2----- --2------- --1------- --1------- --1-------
--x----- --x------- --x------- --x------- --x-------
--3----- --3------- --3------- --2------- --2-------

You can hear the intervals "walking" down . . . .

Good idea, but IMO those are strange voicings for those chords - (1st inversion drop 3?).

I'd suggest:
--x----- --x------- --x------- --x------- --x-------
--5----- --5------- --4------- --4------- --4-------
--4----- --3------- --3------- --3------- --2-------
--5----- --5------- --5------- --4------- --4-------
--3----- --3------- --3------- --3------- --3-------
--x----- --x------- --x------- --x------- --x-------

Here's another:
--7----- --6------- --6------- --6------- --5-------
--5----- --5------- --4------- --4------- --4-------
--5----- --5------- --5------- --5------- --5-------
--5----- --5------- --5------- --4------- --4-------
--x----- --x------- --x------- --x------- --x-------
--x----- --x------- --x------- --x------- --x-------

[Patrick2]

JonR . . . . LOLOLOLOLOL . . . . strange voicing indeed!! . . . . LOLOLOL. I can see where I might have confused the heck out of you. Not being at all familiar with how to correctly draw out the fret chart in the post .. . I put the high E on top and the low E on the bottom. (1st fret 2nd string being a C. . . 3rd fret 6th string being a G)

So, when I tried your fingerings . . they were equally goofy. Then, I inverted it to low E on top of the chart and high E on the bottom. Your post of a CMaj7 3rd poisiton on the inside set of 4 strings accomplishes exactly the same. I actually used to practice them on the inside set of 4, the top set of 4, the bottom set of 4 and the set I showed (upside down) in my post.

So . . . now I've learned how to show a chord properly. Thanx!!!

[edh]

I thought a diminished7 chord formula was: R b3 b5 bb7

[AlsoRan]

I think they were saying the same thing with the "d7", which is the same as your double flat "bb7."

I have never have seen that "d7" before, ed.

[yaclaus]

@Patrick2: Sarcasm?

[JonR]

JonR . . . . LOLOLOLOLOL . . . . strange voicing indeed!! . . . . LOLOLOL. I can see where I might have confused the heck out of you. Not being at all familiar with how to correctly draw out the fret chart in the post .. . I put the high E on top and the low E on the bottom. (1st fret 2nd string being a C. . . 3rd fret 6th string being a G)

So, when I tried your fingerings . . they were equally goofy. Then, I inverted it to low E on top of the chart and high E on the bottom. Your post of a CMaj7 3rd poisiton on the inside set of 4 strings accomplishes exactly the same. I actually used to practice them on the inside set of 4, the top set of 4, the bottom set of 4 and the set I showed (upside down) in my post.

So . . . now I've learned how to show a chord properly. Thanx!!!

Hmm?? Unless this is some kind of deep sarcasm here, your chords look quite clear to me: 6th string on bottom, as in my tab, your Cmaj7 voicing G-E-B-C from bottom to top. Not confusing at all. (If you did originally post them the wrong way up, they were correct when I saw them.) All the right notes for Cmaj7 (and the others), but just - IMHO - an unusual voicing to choose.

[JonR]

I thought a diminished7 chord formula was: R b3 b5 bb7

Yes, that's a common way of spelling it. rpguitar and I were just using abbreviations for "minor" (m) and "diminished" (d) for the respective intervals. This is more correct theoretically, and can sometimes help avoid confusion.

[Patrick2]

Hmm?? Unless this is some kind of deep sarcasm here, your chords look quite clear to me: 6th string on bottom, as in my tab, your Cmaj7 voicing G-E-B-C from bottom to top. Not confusing at all. (If you did originally post them the wrong way up, they were correct when I saw them.) All the right notes for Cmaj7 (and the others), but just - IMHO - an unusual voicing to choose.

JonR and yaclaus . . . no sarcasm at all. Although, it certainly does read as though there is. I went back and re-read your chart and . . . . my mistake. Your string lines are exactly as mine are . . . 6th on the botton and first on the top. I mis-read them at first and thought that was where your comments on the strange voicings came from. So, now I'm even more confused.?.? What's so strange about this voicing/inversion? (and I ask that question out of both ignorance and curiousity . . not sarcasm) I use it frequently. Also, what exactly does . . . . "drop 3" . . . mean?

[JonR]

JonR and yaclaus . . . no sarcasm at all. Although, it certainly does read as though there is. I went back and re-read your chart and . . . . my mistake. Your string lines are exactly as mine are . . . 6th on the botton and first on the top. I mis-read them at first and thought that was where your comments on the strange voicings came from. So, now I'm even more confused.?.? What's so strange about this voicing/inversion? (and I ask that question out of both ignorance and curiousity . . not sarcasm) I use it frequently. Also, what exactly does . . . . "drop 3" . . . mean?

OK, I'm just surprised you would choose such an awkward voicing for Cmaj7 when there are a lot of easier ones available. I've been playing maj7 chords for over 40 years (including taking occasional jazz lessons over the last 20 years), I can honestly say I've never played the shape you showed. And now I've seen it, I don't know quite when or where I would want to. (It does sound quite nice, and I might use the top E-B-C part, but I see no good reason to include the low 5th. If I left that out, I could find easier E-B-C shapes higher up. But it's still not a sound I'd find a common use for.)
I mean, there's nothing really wrong with it. It's just - in my experience - unusual. I didn't mean to sound dismissive or critical, just surprised.

"Drop 3" means you take a close-voiced chord, take the 3rd note down from the top and lower it by an octave.
So a 1st inversion Cmaj7 is E-G-B-C (bottom to top). Take the G and drop it an octave and you have a "drop 3" voicing.
Most guitar chord shapes (at least 7ths) are drop voicings of some kind, because it's rarely possible (or comfortable) to play all 4 notes in close voicing.
Eg, my Cmaj7 was a "2nd inversion drop 2": G-B-C-E, with the C lowered by an octave. (With a bit of nasty stretching, a close-voiced G-B-C-E is possible, but not something I'd ever want to play.)
I don't care that it's a "drop 2", btw, I wouldn't choose it for that reason. I just find it easy and useful, and like the sound.

[Patrick2]

OK, I'm just surprised you would choose such an awkward voicing for Cmaj7 when there are a lot of easier ones available. I've been playing maj7 chords for over 40 years (including taking occasional jazz lessons over the last 20 years), I can honestly say I've never played the shape you showed. And now I've seen it, I don't know quite when or where I would want to. (It does sound quite nice, and I might use the top E-B-C part, but I see no good reason to include the low 5th. If I left that out, I could find easier E-B-C shapes higher up. But it's still not a sound I'd find a common use for.)
I mean, there's nothing really wrong with it. It's just - in my experience - unusual. I didn't mean to sound dismissive or critical, just surprised.

"Drop 3" means you take a close-voiced chord, take the 3rd note down from the top and lower it by an octave.
So a 1st inversion Cmaj7 is E-G-B-C (bottom to top). Take the G and drop it an octave and you have a "drop 3" voicing.
Most guitar chord shapes (at least 7ths) are drop voicings of some kind, because it's rarely possible (or comfortable) to play all 4 notes in close voicing.
Eg, my Cmaj7 was a "2nd inversion drop 2": G-B-C-E, with the C lowered by an octave. (With a bit of nasty stretching, a close-voiced G-B-C-E is possible, but not something I'd ever want to play.)
I don't care that it's a "drop 2", btw, I wouldn't choose it for that reason. I just find it easy and useful, and like the sound.

Ok, thanks. It's true that I don't use the Maj7 fingering too often. . . infact, rarely. But, I use the dom7, m7, m7b5, dim derivatives of that fingering all the time.

[bako]

Drop 2 and 3 are the basic chordal language for guitar because every inversion of every 7th chord is relatively manageable to play. G E B C is a common voicing and in my opinion worked fine in the example. I like that the root was in the lead voice while the notes below gradually added flats progressing from Ma7 - Dim.

By common I mean that it is widely known and not that everybody does or should use it all the time.
We all have our favorites that serve our individual purposes.
One persons strange is the others normal.

[yaclaus]

I wouldn´t call the voicing that unusual either. I think drop 3 voicings are beautiful.
What does drop 3 mean? It means the third note from the top is dropped an octave.

Example:

Gmajor7:

5
3
1
7

Drop the root an octave and we have this standard voicing:

x
3
4
4
x
3

At this moment I am making charts of a bunch of chords and their drop 2,3 and 2&4 voicings so that I always know
a chord I can play no matter what the melody note is. I´ll give you a sample of a major chord - more will follow soon.
It gets really interesting when you do it with chords like 7#9 - all of a sudden you can play this chord in 16 different ways.
I used to know only of 2 ways to play it!

[JonR]

Drop 2 and 3 are the basic chordal language for guitar because every inversion of every 7th chord is relatively manageable to play.

Sure.

G E B C is a common voicing

If you say so. It's not been part of my experience, probably because it's too tricky to be worth it (IMO) - I mean in the kind of music I play.

and in my opinion worked fine in the example. I like that the root was in the lead voice while the notes below gradually added flats progressing from Ma7 - Dim.

Agreed. I preferred it with the root on bottom of each chord, but YMMV, naturally .

By common I mean that it is widely known

I can see that in theory, in that drop 3 is a common option for many chords. It was that specific one (with such a low G) that I felt was borderline useful.

We all have our favorites that serve our individual purposes.
One persons strange is the others normal.

Sure .

[chrisb587]

Hi Patrick

First time entry here on JGO

Really like this 5 chord run - especially that first chord - have heard that somewhere on a cd I own -

but to clarify - that final chord in the run is Cdim7 (and not Cdim) - isn't it ?

Best

Chris

[yaclaus]

correct, the "a" is a bb7 interval so the voicing is a Cdim7/f#

[JonR]

correct, the "a" is a bb7 interval so the voicing is a Cdim7/f#

Or F#dim7 (F# A C Eb).
Ie - to get all pedantic on your asses (again), the "A" in Cdim7 should be "Bbb".
In this case, it's a "common-tone diminished", rather than the vii chord in a minor key (which - if we call it Cdim7 - would be the somewhat mythical key of Db minor).

However, as a ctd, it still (classically) ought to be called something different from Cdim7, namely D#dim7 (D# F# A C) or F#dim7, with the altered tones resolving upward. (Not that us jazz musicians need to care about that...)

IOW, while this 5-chord run is very nice in itself, the true identity of the dim7 (its best name) may depend on what chord comes after it - where is it resolving to? Back to C? Or somewhere else? (It could go to Db/C#, E, G or Bb, major or minor chords, or as a ctd to Eb, F#/Gb or A.)

[yaclaus]

You´re right. Didn´t think about it although I consider myself to be sharp. LOL

[Patrick2]

Hi Patrick

First time entry here on JGO

Really like this 5 chord run - especially that first chord - have heard that somewhere on a cd I own -

but to clarify - that final chord in the run is Cdim7 (and not Cdim) - isn't it ?

Best

Chris

Look at Roger's (rpguitar) post above, #2. This best explains it, as I learned it a million years ago. But, being one to always go against the grain and a former accapella vocalist . . . to me a chord is a chord, whether it 3 notes or 4, or more.

So, I guess theorists would indeed call the final chord a Cdim7 . . . but, most popular reference that I'm aware of call it a Cdim.

So, a Cdim7, to your point is C, Eb, Gb, Bbb . . . or, as yaclaus got spanked by JonR for referencing an enharmonic, it would be C, Eb, Gb, A

I do agree, that hearing the 3rd, 5th and 7th each lowered a semitone in rapid succession sounds pretty cool . . then, another semitone on the b7 is the icing on the cake. Fingerings on other sets of strings don't allow that smooth flow . . . at least not for my whimpy chops.