To divert audiences or to deflect them? The last four movements of K563 may be thought largely diverting, thus fitting Mozart’s title. But the long first, with both halves marked to be repeated, hardly does; and the second, an Adagio of serious intent, commands a concentration well away from the diversionary. Mozart apparently left no clues about the work’s character. In a letter to Constanze from Dresden on April 16, 1789, he simply says “I introduced the Trio I wrote for Herr Puchberg at this little musicale – and we played it quite decently.”

Trio Zimmermann suggests that this “synthesis of a learned display of three-part writing and a popular genre” (Charles Rosen) is closer to grass roots, and they narrow the gap between the learned and the popular. The conception is lighter than expected, the slow movement, though artistically articulated, lacking substance even in the coda. Here the swell in sonority meant to be evoked by tied single and double-stopped notes is understated, as is the pianissimo mysteriousness of the sparsely scored B flat minor Variation 3 of the fourth movement. A studied detachment prevails which, however, dissolves as the Minuets and Trios embody the dance, and the finale swings.

No detachment in Schubert’s unfinished one-movement Trio either. The musicians are consistently sympathetic to changing facets that reflect a 19-year-old composer trying to find his own voice. And BIS’s SACD recording is throughout of a bloom and lucidity that captures the subtleties of performance.