Unknown chord

That's the moveable form of the diminished 7th. The cool thing is that it can be the diminished 7th (root, flatted third, flatted fifth and double flatted seventh) of any of those notes:

Edim7th = E, G, Bb, C#

Bbdim7th = Bb, Db, Fb (which is E), G

C#dim7th =  C#, E, G, Bb

Gdim7th = G, Bb, Db, E

The other really cool thing about this form is that this chord will repeat itself every three frets. So

xx2323     =   xx5656    =    xx8989    =   x x 11  12  11  12

The diminished 7th is used a lot in jazz and is often called a "full diminished" (a "half diminished" being what the rest of us would refer to as a diminshed chord). It used to be used a lot in pop as well, particularly in old Motown songs. It's a great chord because you can resolve it in so many different ways.

There is also a very involved bit of theory where this would be called the "V 0/9" chord, but let's not get into that now. Suffice it to say that your line of thinking concerning the Eb chord ("0" meaning no root and adding on the b9) is going in the right direction.

Hope this helps.

Peace

Hi, Dieter,

It's stacked minor thirds, so it is a diminished chord.

Bb - Db
Db - E
E - G
G - Bb

The nice thing about diminished chords is that the notes will be the same for each of the four roots - so, the chord you have is Bb dim, and Db dim, and E dim, and G dim.

I could be wrong, but I believe some writers do refer to these as diminished 7th's because e.g. the E is a diminished 7th of G and so on. So your thoughts on Edim7 are actually  OK.

Best,

Alan :-)

It's an A7b9 without the A.

So that would make it a 7b9.

Em7b5 (a.k.a. "half diminished 7th") = E G Bb D

Edim7 = E G Bb Db

dhodge don't make me call the "enharmonic police" on you.  ;) (just kidding)

So that would make it a 7b9.

V 0/9 of D if you would. At least from what I remember about an obscure bit of theory (looks like I'll be delving back into Piston in the wee hours of the morning!  

;)  )

Peace

A 7b9 would have a major third (which is implied by the missing A in Argus' chord), but with four different notes already appearing, we don't need to worry about what's left out, as long as what's left in makes sense in terms of thirds.  It can certainly be substituted for the A7b9, though, since it's got four of the five notes, and all the top ones at that.

A m7b5, as Derp suggests, is in fact the half-diminished chord... like Alan said, you need all minor third intervals to make up a diminished 7th.

If you're playing in C, it sure does sound like an E minor chord, since it's got the E-G minor third... but it's usually used in C as a substitute for G, then resolving to G or G7.  You're really going from:

G-Bb-Db-E to
G-B-D-G, or G-B-Db-F

So you're holding the root and moving two inner voices up chromatically.  It ends up sounding like Em in much the same way that Em7 sounds like G6.

Tom

Thanks all. It has all been very interesting and rewarding. Given this is the movable form of the Bbdim7 - Edim7 - Gdim7 - C#dim7, it makes most sense to me to call it a Edim7 because I want do go to Dm7 next and fretwise I do descend two on average.

So, having fallen in love with this basic jazz progression

Dm7 - G7 - Cmaj7 - Am7 / Edim7

where the "/" in the last measure means "divide measure into 2 halfs", I came up with the following very familiar ending

Fmaj7 - F ??? - Em

using xx3210 , xx3110 and xx9987  as voicings.

The second chord in this sequence spells

F, G#, C, E

which is an Fm (F G# C) chord with a major 7 (E) on top. I'll have a look on this site how this chord is called, but if anyone of you can be bothered to answer it anyway, I'd be so pleased. O yes, and is this really such a familiar jazz ending as I say? I'm not familiar with jazz at all.

Thanks again.

Ah, what a wonderful site this would be, no, it is already. An instant after my question I found it in the marvelous "Guide to chord construction" article.

The chord I mentioned was a minor triad with a maj7 on top and it is called ... a min/maj7 chord.

Being a mere mathematician, could I be more pleased ?

Some possibles but I'm really not sure what to call this. There is a clear chromatic run from the A to the G which I would think would normally be emphasised by an Em voicing that utilised the G on the 5th fret 4th string.
?Caug5/F
?Fm#7
?Fmaj7b3 (better illustrating the chromatic run)
Of course augmented chords are symmetrical too so E or G#aug5/F could apply.
?Fmaj7#9 has just occured to me and is sounding the most feasible. It isn't all that unusual to omit the third in altered chords especially if it's a passing chord and is therefore already implied by the chords around it and for practical reasons aswell.
I really am quite curious and flummoxed by this so I will be taking this up with my teacher and watching this post for any alternative answers.
Richard.

min/maj7 - Though I understand it I've never heard of it,
Thanks,
Richard.

minor/Major 7th is the correct name.  It's not all that common, but it can be put to great use... the spelling should use Ab instead of G# though -- G# gets you 1-#2-5-7, and chords are built in thirds, so 1-b3-5-7 would definately be preferred.

Since chords are built in thirds, and chords use only major or minor third intervals, you've got 8 possibilities for a four-note 7th chord:

diminished 7th (1-b3-b5-bb7)
half-diminished 7th (1-b3-b5-b7)
minor 7th (1-b3-5-b7)
minor/Major 7th (1-b3-5-7)
Dominant 7th (1-3-5-b7)
Major 7th (1-3-5-7)
Augmented 7th (1-3-#5-7)
Augmented triad (1-3-#5-8... stacking three major triads brings you back to the octave!)

Tom