How significant is the tonality of a work of music to our perception of it as performers or listeners? Could a work in D minor have been written in B-flat minor, or is there a sort of nomenclature to keys? The treatises on key characteristics attest to the latter rather than the former, and when we look at the frequency of some keys in the outputs of various great composers, we see that the choice of keys can be greatly significant to the character of a work.
Of the many hundreds of adagios that Mozart wrote, K. 540 is the only complete one in B minor (other than the second movement of the D major flute quartet). This already makes it a bit of an “outlier” among Mozart’s works, but when we consider how rarely it is played in comparison to, for example, the A minor Rondo, K. 511, we begin to see that it has other characteristics that put it at odds with what performers and audiences usually experience from the composer.
For listeners and performers alike, Mozart is most commonly associated with opera. In his instrumental music, the melodies often evoke vocal music in their contour, rhythmic structure and variety. A Mozart melody is an organic unit in itself, which often evokes an unsung line of words. Most of his most commonly played works have such melodies. The B minor Adagio, however, is somewhat different. Here, we don’t get the continuous line of melodic inspiration that we hear in the G minor symphony or in the A major piano concerto, K. 488. Instead, we are confronted by a stark diminished chord in the first bar, which effectively truncates the flow of the melody. After two bars of a jagged melody, rather than have the mellifluous development we expect to hear in Mozart, we hear sharp dynamic changes, rhetorical pauses, and a string of “sigh” motifs. The music makes statements of the most powerful kind, but unlike in other instrumental works of Mozart, underlying are not unsung words, but rather un-acted gestures. Were we to connect these gestures to other works of Mozart, we would probably need to look to his vast string chamber music output (the string quintets in particular) rather than the operas. One indication of that is the unusual use of dynamics in this piece. Mozart’s dynamic markings weren’t as detailed as Beethoven’s. Mozart, of course, did not live long enough to see the many developments of the piano that Beethoven saw in his lifetime, which preoccupied him greatly when he was writing his piano works. Many Mozart concerti, even late ones, are almost devoid of dynamic markings in the piano part, leaving us pianists to rely solely on the orchestral parts and on our musical intuition. The B minor Adagio, however, is marked in great detail. Mozart took great pains to highlight the jaggedness and drama that need to be conveyed. These markings, which wouldn’t make sense in an operatic context, would make perfect sense in a string quintet. One can almost imagine the motion of the bows when the first sforzando strikes on the diminished chord of the first bar.
Besides its un-operatic nature, there are other characteristics that distinguish this work from the rest of Mozart’s output. Not many works of Mozart are so centered around diminished chords, but this one is, in an almost Beethovian manner. In the short development section, the diminished chord is definitely the one that sticks out the most, as it has a disorientating effect on the listener, who meanwhile tries to locate a tonal center to “hang on” to.
And does all of this resolve itself? Mozart does reach the much-desired B major at the very end of the work, but its comforting qualities are ambiguous. It comes after a somewhat torrential passage of broken octaves (also not too common for Mozart, at least not in the form heard in this work), and is by nature quite “developmental,” as it has significant dramatic motion in the inner voices. The minor-ness of the Adagio and the abundance of diminished chords may have been resolved, but not in a soothing manner. And as for the ending, the music disappears into the depths of the piano’s range, and Mozart made sure to remind us of the rhetorical pauses of the opening, which perhaps adds even more to the ambiguity of the work.
So is the choice of key for this work coincidental, or is it in fact intertwined with both the work’s rather odd characteristics and our reception of the work? Although I don’t believe that the two are entirely linked, I do think that the choice of key cannot be coincidental. This work, on many levels, is not the Mozart we know—from its most basic features down to the smallest details.