Chord Distribution Analysis

Chord SymbolCountFrequency
Eb7921.4%
Bbm7511.9%
Abmaj7511.9%
Bbm7b5511.9%
D7sus24.8%
D724.8%
Bb724.8%
Dbmaj724.8%

Key Patterns Detected

PatternFunctionFrequency
Bbm7 -> Eb7Setup (Major Key)5
Eb7 -> Abmaj7Resolution (Major)4
Bbm7b5 -> Eb7Setup (Minor Key)3
Eb7 -> Bbm7b5Resolution (Minor)2
Bm7 -> E7Setup (Major Key)1
Ab7 -> Dbmaj7Resolution (Major)1

Harmonic Highlights

  • The progression utilizes a D7 tritone substitution of the dominant, creating a pungent chromatic approach to the standard Bbm7-Eb7 ii-V cell.
  • Incorporation of the iiø7 (Bbm7b5) provides a subdominant minor coloration that frequently blurs the distinction between Ab major and Ab minor tonalities.
  • The Bm7-E7 sequence functions as a chromatic side-slip, momentarily shifting the tonal center up a half-step to create tension before snapping back to the Ab tonic.
  • Functional secondary dominants (Ab7sus to Ab7) are employed to destabilize the tonic and drive harmonic momentum toward the IV chord (Dbmaj7).

Improvisation Focus Navigating rapid, non-diatonic ii-V cells using the Ab whole-tone scale and chromatic enclosures to bridge jagged harmonic shifts.

Difficulty Rating 4/5: The erratic harmonic rhythm and abrupt side-slipping modulations require advanced melodic agility and a sophisticated grasp of chromatic voice leading.