I was learning about extension chords where I stumbled upon a question: if we play Cmajor11(sharp 13), wouldn't that have the note B flat which is supposed to be there in dominant chord? Shouldn't that make the Cmajor11 into a Cdominant11 or something like that?

I tried experimenting around and even thought that it could be both, but then I also had the question, if sharp 13 in a major 7 chord can be considered an avoid note or not.

  • 2
    @Aaron’ answer sums up things clearly, +1. I would like to offer a few comments. First, in several decades of being a musician I have never encountered a #13 chord so this chord is more theoretical than practical. Secondly, 11th chords with a major 3rd are also extremely rare because for example, in a C chord the E and F in the chord create a very dissonant b9 interval. It is much more common to use a sus4, replacing the 3rd with the 4th. Major chords, either maj7 or dominant 7 much more commonly will use a #11 instead of an 11 for more of a Lydian sound. – John Belzaguy Jan 19 at 7:29
  • @JohnBelzaguy - interesting (maybe) that a dom 13 chord already contains that A# (Bb) note, and often sounds better without the 11th - for the reasons you quote. Like you, never had the misfortune to meet a maj 11#13 chord in real life. But just by spelling, they're not the same. – Tim Jan 19 at 8:54

A complete CMaj11(#13) chord is spelled C E G B D F A#, and a C11 (that is, Cdominant11) is spelled C E G Bb D F.

So these are not equivalent, because one contains B natural and the other does not.

However, it's true that both chords contain the enharmonically equivalent (i.e., they represent the same pitch) A# and Bb. The difference in spelling relates to technical/theoretical differences in how those pitches are used in context.

In jazz/pop contexts, chord spelling is often more a matter of convenience as ease of reading/understanding, but the underlying theory suggests that a #13 (A#) should move upwards; whereas a b7 (Bb) should move downwards.

As to whether the #13 would be an avoid note against a major7 chord -- more likely than not. It would be highly dissonant against the major seventh (A# against B), but could be quite useful in an appropriate musical context.

@JohnBelzaguy's comment on the OP is recommended reading. It explains how these chords are used (or not used, as the case may be) in practice.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.