At some point, C7 and B♭13 became two of my favorite chords, so I've become interested in some chord progressions that contain these two in succession. I'll outline some ideas and my thoughts on them below:

  • F major: contains both the root and major thirds for both C7 and B♭13. However, it also does not contain the A♭ you'd expect in the 13 chord (or so I understand how chord notation like this typically works)
  • F (harmonic) minor: this one has an A♭ and an E, but also has a D♭ (so it would become C7, B♭ m13)
  • F (melodic) minor: with the chords placed at the right point in the melody, this may be a solution

What all these have in common is C7->B♭13->F (or V7->IV13->I). What would be some other suggested progressions (or ones that reverse the order of the C and a B chords)?

P.S. I added the Jazz tag due to extended chords being much more common in jazz than in other music I play.


For a famous example from the repertoire, check out Herbie Hancock's Watermelon Man; measures 9--14 of the form alternate between extended C and B♭ harmonies. (0:30 to 0:39 is the section in question; it alternates C--B♭--C--B♭--C--B♭ before resolving to F.)

Otherwise, you could always use a dominant seventh chord as a German augmented sixth; do to so, conceptualize the C and B♭ as C and A# and move these pitches out by half-step to a B7 chord. Thus your progression could be something like B♭13--C7--B7--E. It might sound strange out of context, but in the right context it could be really nice.

Try it the other way, too, using B♭13 as an extended augmented sixth. In this case, B♭--A♭ becomes B♭--G# that will resolve outward to an A7 chord. What's great here is that every tone either stays in common or moves by a half-step, creating a very smooth change in harmony; emphasize and hold over the G to really make it sound great!

  • B♭--A
  • D--C#
  • F--E
  • G#--A
  • C--C#
  • E♭--E
  • G--G

You might also try resolving to G (B♭13--C7--D7--G) or E♭ (C7--B♭13--E♭).

This isn't even getting into the issue of tritone substitutions, where the C7 can substitute for F#7 and lead straight to B.

Once we get to jazz we see that pretty much any chord can follow pretty much any other chord; after you've tried some of these ideas, just pick up the instrument and start experimenting on your own to see what works and what doesn't! Just remember that not everything sounds great out of context; if you don't like the way two chords sound, put them in a larger context and see if that changes anything.

  • Thanks for the tip about context: those two chords sounds really next to each other in isolation
    – cjm
    Jul 31 '16 at 15:20
  • Since this is more of a Jazz context and not Classical, I think it would be better to refer augmented sixth chords as tritone substitutions instead.
    – Caleb
    Jul 31 '16 at 16:09
  • Fair enough. But as always, it's all about context. If the tritone sub is preceded by a iv6, then it's probably better to view it as an augmented sixth chord.
    – Richard
    Jul 31 '16 at 16:19
  • @cjm, I think you forgot the most important word of your comment :-)
    – Richard
    Aug 1 '16 at 10:32
  • 1
    @Richard I think my iPhone are it
    – cjm
    Aug 1 '16 at 14:46

In a blues context these chords are very common. A standard blues is based on dominant seventh chords, so for a blues in F, the I chord is F7, the IV chord is Bb7, and the V chord is C7. Note that a blues progression is not based on a single scale, so it's pointless to look for a scale containing all chord tones. Also note that all chords are basically dominant chords, and that you can add tensions (such as the 9 or 13, or even altered tensions on the V chord) if you like.

Now for the progressions: in a standard 12-bar blues in F, bars 9 - 12 are

| C7 | Bb7 | F7 | C7 |

Make a Bb13 out of the Bb7 if you like. An example for the sequence Bb7 => C7 would be

|| F7 | Cm7 F7 | Bb7 | C7 ||

which also has a bluesy feel to it (due to the F7 and the Bb7), but which is not part of a standard blues progression.


If I understand what you're looking for,any tune, melody , song doesn't have to only contain the diatonic notes from its key. Especially in the jazz field, but still commonly in lots of different genres.

If you want some sort of justification for using notes outside the specific key, then 'because it sounds good' is a good enough reason. To give a bit of theoretical sense, not only can (and are) notes, thus chords from the key itself commonly used, but also those borrowed from the parallel key.

So, If we consider you're in F major, all those 7 chords built on those 7 diatonic notes will fit smoothly, but also those 7 notes (and chords) from F minor. Maybe that's where the Ab magically appears from?

As always, the theory tries to explain the facts, but it still remains theory, and will, in music, never become the law.



Given that you've asked for examples of chord progressions, here are four different chord progressions that use C7–B♭7, with some examples from jazz/blues songs:

  1. use C7–B♭7 as I–♭VII in the key of C7
  2. use C7–B♭7 as ♭VII–♭VI in the key of D min
  3. use C7–B♭7 as ♭III–♭II in the key of A min
  4. use C7–B♭7 as V–IV in the key of F

Some illustrative songs:

  • Progression 1 (I–♭VII) can be found in Killer Joe (here and here): measures 1-8
  • Progression 1 (I–♭VII) can be found in Doxy (here and here): measure 1
  • Progression 2 (♭VII–♭VI) can be found in Hit the Road Jack (here and here): measures 1-2
  • Progression 4 (V–IV) can be found in an F Blues (here): measures 9-10
  • Progression 4 (V–IV) can be found in Watermelon Man (here and here): measures 9-14

A couple notes:

Doxy is originally in the key of B♭ and used B♭7–A♭7, but you can transpose the song to the key of C to get C7–B♭7 in measure 1.

Hit the Road Jack is originally in the key of A min and used G7–F7, but you can transpose to D min to get C7–B♭7. The lead sheet doesn't show these chords as dominant 7th, but if you were to add a 7th it would be flat not natural.

I'll try to find an example of progression 3 and add it to the answer. The turnaround in the final two bars of Lady Bird gets close to using E♭7–D♭7 as a ♭III–♭II in the key of C, but it's not quite what you've described because of the intervening A♭ chord (E♭7 – A♭ maj – D♭7).

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