Composer Note:Concerto Quaternio
is in three movements, set in an overall fast-slow-fast format. It features four soloists (violin, flute, oboe and trumpet), each of whom leads one of the chamber ensembles into which the orchestra is divided (the percussion section constitutes a fifth ensemble). Each group, more or less registrally distributed, contains not only representatives of the three standard orchestral choirsstrings, woodwinds, and brassbut also a “keyboard” instrumentpiano, celesta, harpsichord, and harp (the latter in the oboe-led ensemble). These voices are used instrumentally.
The keyboard instruments and harp often accompany and support their respective solo partners, an association most noticeable in the cadenzas with which the slow movement ends.