Editor diminished symbol

[Drooly]

I'm teaching myself a diminished chord progression up and down the guitar keyboard in all the keys. How in the editor to I tell it to play A dim or C Dim for example?
Thanks

[pdxdjazz]

Lower-case "o" is the symbol for diminished chord quality.
)BOB

[Drooly]

Thanks Bob. Yeah I'd read that elsewhere on the forum but the guitar chord symbol that "o" creates is not A dim but A dim7 . Close but not quite right. E with a "o" is B6 shape.

Now I'm no music theory expert but these chord shapes its giving look and sound different to what they should be. What am I doing wrong I wonder?

[pdxdjazz]

As you probably know, in a diminished chord, every note is a minor third apart and the chord can be called by any of it's notes. So there are only three diminished chords (not counting inversions) which can accommodate all twelve roots.
The diminished seventh chord contains the further diminished 7th (enharmonicly the 6th)
Co=Co7= C,Eb,Gb,Bbb(A)
The half-diminished ∅ (min7b5) contains the (already once diminished) 7th. C∅= C∅7 = C,Eb,Gb,Bb

That's why the o7 chord will slide up (or down) three frets and work. The ∅7, not so much.
)BOB

[Drooly]

Stunning reply. I think understood most of it too thanks Bob
Chris

[MacAlex24]

Actually, I think I understood Bob's explanation, but how can I write the following chord: Cm7#5 or otherwise Cm7b13 ? I thought it could have been Cdim7, but this won't be accepted in iReal Pro notation rules. Or do I have see this chord as Ab add9? Could anyone help me with this, please?

[pdxdjazz]

Actually, I think I understood Bob's explanation, but how can I write the following chord: Cm7#5 or otherwise Cm7b13 ? I thought it could have been Cdim7, but this won't be accepted in iReal Pro notation rules. Or do I have see this chord as Ab add9? Could anyone help me with this, please?

The Co7 works in the player when you use the "o" symbol.
However, it's not the chord you seek as it has the b5 rather than the #5.

Ab add9 has the correct notes. You could also write it Ab add9/C.
C-#5 is accepted, so is C-#5/Bb
Depending on context, there might be other chord choices.
)BOB