Suspended and add chords
- Csus4 = C F G; Csus2 = C D G: without a third, neither major nor minor.
- Cadd9 (Cadd2) = C E G D: an enriched major, very guitaristic.
- C6 = C E G A; C6/9 = C E G A D: an “open” close typical of bossa and jazz.
- Mu chord (Steely Dan): C D E G, with the close second under the third.
Slash chords
Chord / bass note.
- Inversions: C/E, G/B.
- Foreign bass: F/G (F A C over G) = G11 without the third: the “soft” dominant of gospel and pop.
- Bb/C = C9sus4; D/C = Cmaj7#11 (Lydian); Ab/Bb = Bb9sus4.
- Am7/C = C E G A = C6: the same set of notes changes name depending on the bass.
Hybrid chords (Berklee: hybrid voicings, compound chords)
A triad in the right hand over a bass that isn't part of it. They produce modern sounds without the tension of the tritone: Eb/F, Dm/G, Bb/C. They are ideal in R&B, neo-soul, K-pop ballads and lo-fi.
Practical use
- Replace G7 with F/G for a softer cadence: Dm7 – F/G – Cmaj9.
- Suspended pads (Csus2 – Gsus4) for an ambiguous bed under a rap.
- Resolving sus4 → 3 (Gsus4 → G) reproduces in miniature the 4–3 suspension of fourth species.
Real example
Mu chords are the harmonic signature of “Peg” by Steely Dan (1977); “Maiden Voyage” by Herbie Hancock (1965) is built entirely on sus chords.