Structural Endings: It’s all about that Bass!
There is a special moment in nearly every piece that communicates to an audience that the end is near - not that the end has arrived but rather a demarcation point that suggests that everything following might be fluff. Perhaps it isn't fluff after all, but the cadence at this point is usually the second-most strongest, gut-satisfying one of the piece. (The first one, of course, being that moment of arrival at the recapitulation or at the return of the main theme.)
A structural ending is found at the point of a massive V - I, or better, a V7 – I motion. Below is an example from the end of the first movement of Beethoven’s Piano Sonata in G Major, op. 14, no. 2. Finding the structural ending is made much easier if one studies the bass line. The passage can be seen and heard as a “trial and error” as Beethoven stumbles on D (the dominant) over and over again and in doing so forestalls the inevitable V7 – I cadence. In measure 179, he begins as series of three noodling chromatic climbs, each ending on D. The last doubles the rhythm to quarter notes on C#s, then to Ds, as if to say “maybe this time Beethoven will find G”. And he does! The following chord structures circle around on a pedal point G.
Chopin pulls an interesting stunt in his Waltz in A-flat, op. 42. The form is a typical rondo with several recurring sections. The grand transition to the structural ending starts with theme D. However, on its second run through here (pictured below), its bass line switches to a descending line, finally settling on E-flat just before the return of the B theme with its running stream of right-hand eighth notes.
Theme B appears six times in the piece (the A theme only appears twice!) with each of the first five occurrences featuring an oscillating V-I motion in the bass. The sixth time, he chose to write a pedal point E-flat instead, prolonging the feeling of the suspended V before the structural ending. This is followed by a wild cadence, flinging the theme into the upper regions of the piano. The dramatic departure ends on a I chord in root position. The rest - a Coda in this case - relies on an A-flat pedal point. Chopin uses additional stalling techniques in the last line with final-sounding chords that still do not quite end the piece, leaving that necessary task to the grumbling fury of octave bass notes in the last two bars.
Finding the structural ending of a work affects its interpretation dramatically since the largest event of the piece should have the greatest weight. This is achieved mainly through the flex of rubato and control of dynamics to heighten drama. But remember, it's all driven from lowest line upwards. It really is all about that bass.