Chord sequence

Bbm7, A7, Abm7, G7

B♭m7 A7 A♭m7 G7

Tempo 120 BPM

Rootless Shells Guide tones Rooted shells Rooted Drop 2

Four-note rootless voicings in their two forms, with the 3rd or the 7th on the bottom, played over the root.

Customize each chord

Bbm7
A7
Abm7
G7

Analysis

Heard in F# major

Each chord's roman numeral and role in F# major
Chord	Numeral	Role
B♭m7	♭iv7	Diatonic
A7	subV7/ii	Tritone substitute for V7/ii
A♭m7	ii7	Subdominant
G7	?	Outside the key (bII7)

Progressions in these changes

All the chords

Chromatic iii-bIII-ii-bII Progression in Gb

The iii-VI-ii-V turnaround with both dominants replaced by tritone substitutes, so the roots descend by half steps from iii to I.

Scales to play