I want to quickly have a look at this chord I stumbled across in Charles Mingus’s 1955 piece, Jump Monk, which can be found on the album, Mingus at the Bohemia. Mingus’s hard-bop tribute to Thelonious Monk deserves pages of its own but I really just want to focus on a chord in the ‘B’ section, which kicks in at 1.46.
The B section is in Bb minor and opens with the horns traversing the Bb harmonic minor scale before flirting around some chromatics and finishing with a syncopated line. The chords for this section are written Bb-6, Bb-∆, Cø, F+7, which is i, iiø, V+ in Bb minor.
N.B The sub-octave treble clef is being used for the chordal examples.
It’s the second chord that I want to look at. Ordinarily, Bb-∆ would use the notes Bb, Db, F and A, but I prefer to think of it as an Eb chord functioning as either a IV in Bb minor. It could also bee seen as aV in Ab which is the relative major key of F minor, which the A section is in.
(Sadly, I can’t find a way of playing this on a guitar, as the voicing has notes too close to each other. I’ve written an Eb9 in the above example but a simple Eb7(b5) would also work nicely.)
The voicing I prefer to use for the first chord is a simple Bb-7 (Bb, Ab, C, Db, F) which leads nicely to an Eb9 by switching the bass note from Bb to Eb and dropping the Ab to a G (Eb, G, C, Db, F). Adding the A natural from bar 2 gives us this:
Eb, G, C, Db, F, A.
Here’s the chord on its own:
I would spell this Eb13(b5) as it has the notes from Eb7 (Eb, G, Db), C is the 6th degree (which would read as a 13) and the A is a flattened 5th degree (Bb > A).
A nice easy way to remember this would be C minor first inversion in your left hand (Eb, G, C) and Db augmented in your right hand (Db, F, A); or, perhaps even easier, an Eb7 shell voicing (Eb, G, Db) with an F triad over the top (F A C). Starting the F triad in different places will give you different top notes which affect the overall feel of the chord.
And… voilà! The chord can slot into any situation preparing the tonic in a major or minor key or, like in the Jump Monk example, prepare a iiø.
*edit* It got its own page.