17 string instruments and percussion

Many of Anders Hillborg’s pieces require extensive preparation. In the case of this one for 17 string instruments and percussion (Japanese wood blocks, bamboo chimes, and castanets—and castanets for the strings players too!), each of the string instruments (indeed, each of the strings) must be tuned slightly differently. The elaborate tuning scheme Hillborg calls for, where strings are tuned as much as a half tone above or below their normal pitches, allows the ensemble to produce the fragile microtonal harmonies that are heard throughout the piece almost exclusively with open strings and natural harmonics. With this combination of precisely calculated microtones and the shimmering texture of harmonics and unstopped strings, Hillborg constructs a highly distinctive sound world, and one which resonates with both terms in the piece’s title: as the Finnish composer Jouni Kaipanen has suggested, “mechanics” aptly characterizes compositional technique, while “celestial” neatly captures the music’s prevailing quality. Celestial Mechanics is not an uninterrupted string of “delicate pearls which evoke the harmony of the spheres,” however. Harsh, even violent passages (including one marked “brutalissimo”) suggest a distinctly terrestrial realm—though these ultimately serve to heighten the sense of the ethereal the work as a whole projects. Celestial Mechanics was commissioned by the Swedish Radio Symphony Orchestra, and was premiered by that group under Esa-Pekka Salonen in October 1986.