The 7–6 suspension

A voice prepared as a consonance is held while the bass steps down beneath it, striking a seventh above the new bass on the strong beat and falling one step to the sixth. The chord of resolution is a sixth chord, so the 7–6 is the suspension of stepwise, first-inversion writing — where the 4–3 belongs to the cadence, the 7–6 belongs to the descending scale.

It is the suspension of the walking bass: wherever the bass descends by step under first-inversion chords, the 7–6 turns a plain run of sixths into a line with its own pull. Because its resolution is a sixth chord, not a root-position triad, it carries none of a cadential suspension’s finality — it belongs in the body of a phrase, not its close. Over several steps of descent, one resolution becomes the next preparation almost automatically, which is why a stepwise bass reaches for it first.

• Sounding the sixth — the tone of resolution — in another voice while the seventh is still held, which announces the sixth chord before the suspended voice can deliver it.
• Attacking the seventh fresh rather than holding it over from a consonance in the previous chord, which skips the preparation the whole device depends on.
• Resolving the seventh upward or by leap instead of falling one step to the sixth.
• Reaching for the 7–6 at a final cadence, where its first-inversion resolution cannot supply the root-position arrival a close needs — that is the 4–3’s job.
• Letting the bass leap under the suspended seventh, which breaks the stepwise descent the 7–6 is built to ride.

• Johann Joseph Fux, Gradus ad Parnassum (1725), Liber secundus, fourth species (the ligature) — The seventh resolving to the sixth is one of the two dissonant ties the species admits above the cantus firmus.
• Carl Philipp Emanuel Bach, Versuch über die wahre Art das Clavier zu spielen, Part II (1762), Part II, on the chords of the seventh and their resolution — The accompanist’s treatment: how the figured seventh is prepared, struck and resigned to the sixth.
• Ebenezer Prout, Harmony: Its Theory and Practice (1889), The chapter on suspensions — The classroom codification, including the ban on sounding the tone of resolution against the suspension.