I am a new guy here--having a hard time with this any help will be much appreciated--I have seen a chord described as Abmaj7/add 6 versus Abmaj7 #11 are they the same but written differently? Many thanks
Not quite! The ♯11 is enharmonically equivalent to the ♯4 or ♭5, whereas the 6th is equivalent to the 13th. For an A♭ chord, the 6th is an F, whereas the ♯11 is a D♮.
Perhaps you could quote directly from a source so we can identify the exact source of confusion.
The chord of A♭maj7 contains the notes A♭, C, E♭ and G. Both of the quoted chords will have those.
Add 6: the major 6th note of A♭ is F, so add that into the mix and we have A♭ maj7 (add6).
♯11: the 11th of A♭ is D♭, so when sharpened will become D♮. Put that into the original mix, and we have A♭maj7♯11.
Two slightly different mixes, making two slightly different sounding chords.
11 and 6 are not the same. The pairs of "the same" notes are:
- 2 = 9
- 4 = 11
- 6 = 13
But that's not all there is to it.
Even though they "sound" the same, they are used in different contexts. In a dominant chord, you will usually find 9, 11 and 13. In a major chord, you will see 6 and 2 (4 is not used alone, it's only seen in "sus4").
Since the only difference between a major chord and a dominant chord is in the 7th (major 7 in a major chord, minor 7 in a dominant chord), when you see just the 9, 11 or 13, the minor seventh is implied. So, even though 6 and 13 are the same:
- C6 is C E G A
- C13 is C E G Bb A