About this work
The powerful interest in folk music and national styles that occurred in 1930s American art, theater, and music inspired a number of works for percussion ensemble, including those by John Cage, Lou Harrison and Edgard Varèse. Henry Cowell, already known for his "ultramodern" compositions, also tried to reflect this expanded musical awareness, as evidenced by this energetic and delightful piece for eight performers. In its way, it is an early kind of "world music," suggesting at times Javanese and Balinese gamelan, African drumming, South American village, South Indian classical instrumental, and of course contemporary American concert musics; but the overall conception is decidedly modern: a self-contained, quietly excited surface of contrasting tone colors. It is dedicated to the innovative and adventurous conductor and champion of modern music, Nicolas Slonimsky.
The composer indicates that most of the parts, except for the difficult xylophone part, can be played by "non-professionals." The "percussion band" necessary to create this timbral panorama consists of instruments of fixed tuning and those of indefinite pitch. To execute the two tuned "string piano" parts, the performers use their right hands to play the indicated pitches on the regular keyboard while their left hands dampen the interior strings in various ways (over several strings, near the bridge, at 1/4 the length of the string, etc.) to produce different harmonic partials. The xylophone part is in standard tuning, but the swift, manic, and rather snaky chromatic part is played with soft mallets, yielding a muted wooden tone. Eight rice bowls (the "jala tarang") of indefinite pitch are arranged according to relative highness and lowness. The same indeterminate relation holds for the two woodblocks, the tambourine (without rattles), and guiro (tapped with stick) pair, the two bongos, the three drums, and the three gongs (struck with padded and wood sticks).
The "ostinato" of the title refers to the invariant, cyclical rhythms of different lengths assigned to each player. The beginning of a cycle is marked by a loudly accented special event: a tone cluster for the string pianos, a major third for the xylophone, the striking of two bowls by the rice bowls player, two woodblocks by their player, two bongos by that performer, and a wood stick grace note on tynhe gongs. Additionally, most of the instruments indicate the end of each cycle with a trill or a tremolo that briefly builds in excitement and anticipation.
The overall dynamic is very soft unless accents are notated; in those cases, the accented events are "brought out sharply." The ensemble sound thus created is like a mysteriously shifting, polyrhythmic mobile exuding a strange ceremonial atmosphere. The last eight measures of the composition gradually build toward an overwhelming climax. This crescendo occurs as an accumulation initiated by a loud cluster in the first string piano, which is then progressively answered by the other instruments.