Typically of Mozart in E flat, the Quartet K493 is a far more mellow and genial work with, in the first movement, something of the relaxed grandeur of the recently composed E flat Piano Concerto, K482. As in the concerto, the first movement has an almost reckless profusion of lyrical themes, which expand and proliferate at leisure. Most pervasive and influential is the theme that establishes the dominant key, B flat, initiated by the piano and immediately echoed by the violin. This idea fertilises the whole of the widely modulating development (moving from B flat minor and D flat major as far afield as D minor), where strings engage in close imitative dialogue against a background of rapid keyboard scales and arpeggios—a common texture in Mozart’s piano concertos. When this theme reappears in the recapitulation on violin and viola, with the cello following in imitation, it again starts in B flat—all wrong for this point in the movement—before the piano smoothly restores the home key of E flat. This ‘wrong key’ entry in the recapitulation demands a resolution in the coda, where the strings reiterate the theme in three-part canon with the simplest tonic and dominant harmony.
The A flat Larghetto, in full sonata form, shares the warmth and chromatic richness of the G minor Quartet’s Andante. But it is a more intense, less decorative, movement, with an impassioned development that begins with a dramatic re-interpretation of the opening phrase—a moment echoed, with another new twist, at the start of the coda. Mozart’s sketches reveal that he discarded two drafts of the finale’s gavotte-like theme before arriving at a version that satisfied him. Again there is an abundance of graceful and piquant melody, though the movement’s chief protagonist is an idea that at first seems to be merely transitional: a brusque unison for the three strings answered by a pleading syncopated phrase on the piano. This idea is rarely absent for long, chromatically expanded just before the initial return of the main theme and, in an echo of the first movement, sounded in close canonic imitation in the coda.
from notes by Richard Wigmore © 2003