Movement I - Measures 75 to 80

Standard procedure in the development section calls for a pre-core (material of lesser emotional intensity) followed by a core (material that is unstable and dramatic). The core consists of a model that is sequenced in different keys.

Beethoven follows this procedure here. Measures 61 to 64 constituted the pre-core; measure 65 began the core. The model (measures 65 to 70) was first stated in B-flat minor. In measure 75, Beethoven begins a restatement in D-flat major. The restatement is interrupted, however, by a modulation to F minor.

In the piano version, Beethoven has consistently used dynamics to highlight the structure of the core. He continues to follow this procedure here. Measure 77, which begins the modulation, is marked pianissimo, as if to whisper "You didn't expect that, now, did you?"

In the string version, however, Beethoven highlights the structure by modifying the accompaniment. Had he followed by pianistic scheme and patterned the accompaniment here after the original model, we would have this:

Instead, Beethoven gives us this:

Rather than simply repeat the earlier pattern, he has the viola echo the cello's arpeggios, leaving the second violin to manage the tremolos on its own. This interplay raises the intensity of this passage, an effect that is enhanced (as observed last week) by the fact that the arpeggios were eliminated altogether in the bridge between the model statements.

In measure 79, Beethoven does something he has not previously done in the core: give the cello sustained notes, rhythmically doubling the melody. We have heard nothing but eighth notes in the cello for the past 14 measures. So the sustained notes provide a dramatic build-up to the climax on the downbeat of measure 80. After the climax, the cello immediately returns to its eighth note tremolos.

None of this drama is present in the piano version with its relentless arpeggios. At least it is not present in the score.It's up to the performer to discover the harmonic narrative and bring it out in performance. Since the string quartet has a greater expressive range than the piano, there is no need for Beethoven to be so coy.

The final measure illustrates some voice-leading considerations. Adding the long line in the cello in measure 79 required changing the bass in measure 80. The bass is now a D rather than a B-flat. But a second inversion vii/V chord resolving to V does not provide the dramatic half-cadence Beethoven wants. So he flats the D, changing the chord into a German sixth.

Note the way Beethoven resolves the German sixth at the very end of the phrase. Later composers would resolve the viola's A-flat to a G, since the German sixth came to be considered as an exception to the prohibition against parallel fifths. Beethoven, however, still feels the need to avoid the parallel fifths and resolves the A-flat upward to a C.  He also meticulously drops the viola's F down an octave before moving to the A-flat. Why? So that he approaches the dissonance (A-flat against the melody's G) in contrary motion. Approaching the dissonance in similar motion (from the high F) would not sound as good. Such Bach-like attention to detail is one of the things that makes Beethoven's music so exceptional.