Passing note, passing chord

The third is a highly favored interval in chord construction. Consequently its diatonic filling-in – connecting root and third, third and fifth, or fifth and seventh – is encountered frequently. Any third may be expressed melodically as two consecutive seconds, either ascending or descending. The internal pitch of such a line clashes with its context: it “passes” between pitches that have a more secure footing within the immediate chordal framework.

A passing note occurs least obtrusively in a weak metrical position. Yet it may be emboldened in various ways. In filling in an F–D third, Friedrich Wilhelm Marpurg places passing note E in a relatively strong metrical position, against a change of bass from G to B [5.1a]. An eighth-eighth-quarter rhythm for F–E–D would have resulted in the juxtaposition, a consonant element of the G-B-D-F chord. Marpurg's quarter-eighth-eighth rhythm instead places bass B against passing E. As a result, a dissonant fourth follows a dissonant seventh. The interpretation of this situation is especially delicate because traditional dissonance-resolution strategy mandates that the F of a G chord should resolve to an E. Yet according to Marpurg it is not this E that fulfills that role, but instead the E on beat 3. The language he uses to express this idea in 1757 is clear and persuasive: