No composer understood wind instruments better than Mozart, so the solo lines in the Sinfonia Concertante are composed with a fine feeling for their special qualities: the oboe’s expressive, penetrating voice; the clarinet’s liquid fluency over a wide range; the horn’s elegant adventures in its upper octave; and the bassoon’s many functions as bass line, tenor line, or tune.
Their interplay is balanced and lucid, and they have a neat cadenza at the end of the first movement, carefully composed, as such cadenzas have to be, not left to group improvisation. The slow movement is, unusually, in the same key, E-flat major, and unusually long.
In contrast, the finale is a series of variations on a brief and simple theme. One phrase from this melody is taken directly from the second main melody of the first movement. Ten variations reproduce the outline of the theme with increasingly decorative display from the soloists. Then the tenth variation dissolves into an Adagio before the jolly close in a hunting style.
Here is this lovely work by Mozart:
