Does C° also indicate a major seventh chord?
I had always thought that this notation indicated a major seventh chord: [C°]. At least it seemed to make sense that way in some of the chord sheets I have used in the past.
I am now finding that it more commonly seems to represent a diminished chord, as in [Ab°(b13)] or [A flat dim flat 13]. My first question is has anyone here ever seen [°] used to represent a major seventh, or am I labouring under an illusion ;-)
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I had always thought that this notation indicated a major seventh chord: [C°]. At least it seemed to make sense that way in some of the chord sheets I have used in the past.
This must have been an error. As Cmaj7 is a static chord (or eventuell would lead to F) it couldn't be substituted by C°, while latter might have a dominant function to Db, (or E, G and Bb) and certainly can't be replaced by Cmaj7.
Edit:
As the other answers confirm C°7 was never meaning C major 7.`
I've edited the last words ... was never a major 7 as someone could understand A-major 7 ( a was meant as article not as chord).
I have never ever seen "o" denoting a major 7 chord. A triangle can be used for maj7 in some books (e.g. the Aebersold play alongs), and 'o' is always diminished.
You may also encounter a slashed cirle (ø) for half diminished (min7 b5) chords.
While answers are correct that C° means C diminished and C? means CMaj7, there is more to the story here. In jazz, C° is a very common delayed resolution to CMaj7. For example, in a simple ii-V-I:
| Dmin | G7 | CMaj7 | CMaj7 |
it's very common to hear pianists harmonize this with:
| Dmin | G7 | C°7 CMaj7 | CMaj7 |
In this context, the scale typically used over C°7 is C whole-half (enharmonically, C D E? F G? A? A? B). This diminished scale contains the BMaj triad, which resolves up a half step to a CMaj triad when we reach the CMaj7 chord. However, while the C°7 can be voiced with a BMaj triad, this isn't necessarily and isn't always done in jazz. We can simply voice the C°7 chord in its typical fashion.
This isn't all that different from a common-tone diminished 7th chord, which resolves iio7 to IMaj (for example, D?o7 to CMaj). After all, D?o7 has the same notes as Co7. But in a jazz context, the bass is often still playing the I, establishing the progress as io7 - IMaj7.
Lead sheets may show this io7 chord written into the bar, or they may show it above the bar in parentheses to indicate that it's a possible chord substitution. Or, it may not be shown at all, in which case the musician(s) are choosing to add this substitution into the music on the fly.
If you're playing from sheet music that's been handwritten, or perhaps photocopied multiple times, it's not uncommon for the small △ symbol, which denotes Maj7 to end up looking like small circle °, which, as you say, denotes Diminished.
Or if the copyist isn't particularly careful, the circle and triangle can end up looking similar.
Never. C° is always C diminished. C major seventh can be signed with a triangle after the C. Bear in mind that half-diminished is signified by a circle with a diagonal line through it.
Cmaj7 is C E G B.
C°7 is C E♭ G♭ B♭♭.
C half dim. is C E♭ G♭ B♭. Note: they all contain C E G B something.
o a degree sign for diminished triad or o7 for diminished seventh chords.
ø7 for half-diminished seventh chords.
?7 a delta or triangle for major seventh chords.
Other signs are used capital M for major or lower case m for minor, etc.
You may have been mistaking the delta for a diminished sign.
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