Theory & Impro B7b7 - Flattened 7th in a Dominant 7th?

cappers

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Looking at the lead sheet for Beautiful Love for Bb instruments (in Eb) there is a B7b7 chord.

B7 is B D# F# A. Since a dominant chord has a flattened 7th by definition, does the b7 in B7b7 mean the 7th is flattened again to give B D# F# G#?

Thanks.
 
If I enter both chords in MuseScore, they sound identical.
If I try to enter B7b7 in Band-in-a-Box, it outright refuses to register the chord.

I think the b7 is pretty much redundant in this case, as the 7th is already flat in B7.
B D# F# G# is usually notated as B6, I think.
 
@mrblackbat Hi Matthew

This the sheet for Bb:
Screenshot 2026-06-13 at 12.29.17.webp


If it helps, the Eb version is a F#7b9
Screenshot 2026-06-13 at 12.29.49.webp

Thanks
 
Last edited:
In music, we have double sharps and flats, to keep the spelling correct.
So, in the key of B, the seventh is a
form of A.

Even "errors" deserve the correct spelling, are we on the same page blackbat? 😜
 
I understood, possibly incorrectly, that one can't have a chord or notation with both # & b
e.g. BD#F#G# not BD#F#Ab ? I get that the 7th of B is A# so when flatted in a dom7th it becomes A.

No matter, I'll ask the MD if he meant B7b9.
 
I understood, possibly incorrectly, that one can't have a chord or notation with both # & b
Yes you can.
Since a dominant chord has a flattened 7th by definition, does the b7 in B7b7 mean the 7th is flattened again to give B D# F# G#?

Enlighten me please @PiccoloPirate......why Ab and not the enharmonic G#?
If you were flatten a b7 interval, it's a diminished 7 interval. Hence it would need to be spelled Ab as G# is a 6th. However it's moot because

  1. This was a badly written b9 so was never ever a double flatten 7
  2. You can't have a double flattened 7 in a dominant 7 chord, because it would no longer be a dominant 7 as the b7 in a dominant chord is part of what defines a dominant 7 type chrd (along with the major 3).
  3. You do get double flattened (ie diminished) 7 intervals but only in a full diminished chord.

Piccolo Pirate is correct IMO. However I believe it's often OK to write enharmonically incorrect notes when writing out parts if it makes for easier sight reading. But in chords the notes should be enharmonically correct.
 
In music, we have double sharps and flats, to keep the spelling correct.
So, in the key of B, the seventh is a
form of A.

Even "errors" deserve the correct spelling, are we on the same page blackbat?

What are you talking about? The seventh in the key of B would be A#. Both major and minor. If you want to get modal, then natural minor, Dorian, Phrygian, Locrian, the seventh is A natural. There is simply no real occurrence of the seventh being an Ab. And in the context provided, there’s no double flat occurring. So stop talking rubbish and confusing matters for someone who is genuinely trying to learn.
 
What are you talking about? The seventh in the key of B would be A#. Both major and minor. If you want to get modal, then natural minor, Dorian, Phrygian, Locrian, the seventh is A natural. There is simply no real occurrence of the seventh being an Ab. And in the context provided, there’s no double flat occurring. So stop talking rubbish and confusing matters for someone who is genuinely trying to learn.
Capper's incorrect guess about the B chord having a double flatted 7th would indeed be Ab, not G# (the major 6th/13th). But as Pete pointed out, it would no longer be a dominant 7th, but a weird sort of diminished chord.

I agree that entire line of thought is pointless, irrelevant and confusing. It's simply a typo. Trying to give it any other meaning is silly.
 

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