Major I-VI-ii-V Progression in Ab

Tritone substitutes

Abmaj7 B7 Bbm7 A7

Each dominant 7th that resolves down a fifth becomes the dominant a tritone away, which shares its 3rd and 7th, so the bass moves by half steps.

Related ii chords

Abmaj7 Cm7b5 F7 Bbm7 Eb7

Each dominant 7th gets the ii chord of its own ii-V before it, half a dominant's time each.

Backdoor dominants

Abmaj7 F7 Dbm7 Gb7

Each V7 resolving to a major chord comes in by the back door from bVII7, with iv7 for its ii, borrowed from the minor key.

Passing diminished chords

Abmaj7 Adim7 Bbm7 Eb7

Diminished 7ths on the half steps between chords a whole step apart, or in place of a dominant whose 3rd is a half step above the chord before.

Major I-vi-ii-V

Imaj7 vi7 | ii7 V7

In Ab: Abmaj7 Fm7 Bbm7 Eb7

The basic turnaround: diatonic chords falling in fifths from vi back to I, two to a bar, to bring a tune back to the top.

Major iii-VI-ii-V

iii7 VI7 | ii7 V7

In Ab: Cm7 F7 Bbm7 Eb7

The I-VI-ii-V turnaround with iii, which shares three notes with the I chord, standing in for the tonic.

Diminished Passing Turnaround

Imaj7 ♯i°7 | ii7 V7

In Ab: Abmaj7 Adim7 Bbm7 Eb7

The I-VI-ii-V with a diminished 7th chord on #I in place of VI7, so the bass rises by half steps from I to ii.

Tritone Sub Turnaround

Imaj7 ♭III7 | ii7 ♭II7

In Ab: Abmaj7 B7 Bbm7 A7

The I-VI-ii-V with tritone substitutes for its dominants, bIII7 for VI7 and bII7 for V7, so the bass falls by half steps from bIII back to I.

Chromatic iii-bIII-ii-bII

iii7 ♭III7 | ii7 ♭II7

In Ab: Cm7 B7 Bbm7 A7

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

Tadd Dameron Turnaround

Imaj7 ♭IIImaj7 | ♭VImaj7 ♭IImaj7

In Ab: Abmaj7 Bmaj7 Emaj7 Amaj7

A turnaround of major 7th chords on I, bIII, bVI and bII, named after the bebop composer and arranger Tadd Dameron.