For example, if I play
C, should I call this chord Eadd#5/D?
D E G# B looks like a nice E7 voicing to me. over dominant seventh chords we often add the #5 but since theres already a 5 in the chord - namely B - we call it the b13 or (occasionally) b6. You can satisfy yourself they all refer to the same note by counting up in thirds on the keyboard.
So it could be an E7b13/D. I might well drop the /D, depending on context - in jazz, for example, we often let the player choose the voicing. Since there's already a D in E7b13 we dont "lose information" by omitting the /D.
TLDR - its an E7b13. You could call it E7b13/D if you like.
(looks like Peter beat me to it - but this might be helpful anyway)
There really are two questions.
...if I play D, E, G#, B and C...
First, arrange the tones in third to see the tertian chord
C E G# B D
Cmaj9#5/D a major ninth chord with a sharp fifth and the ninth in the bass. That's really stretching things, not a likely chord. If that point is debated, we need to see the harmonic context to know what is the appropriate chord analysis.
However, the portion
E G# B D as
E7/D - a dominant seventh chord in third inversion - is completely ordinary.
If the added tone is notated as
C then it's a flat 13th:
Are there add#5 chords?
I think no. The fifth (altered or unaltered) isn't added to chords. Despite the fact that the fifth can be omitted, it is an essential chord tone not a mere added tone. In the case of omission it is still assumed to be there theoretically.
I think the question then is:
- whether there is a combination of both a
C, both a perfect fifth and a minor sixth over the root,
- or if there is only one tone an augmented fifth above the root which would be properly spelled as
In other words, I think the sharp (or flat) fifth should only be used when there is actually an alteration of the fifth of the chord. If the fifth is not altered, then an additional tone must be involved and it should be spelled and notated appropriately, most likely a
So if this chord actually had used a sharp fifth, it might have been something like
D E G# B# a