By DANIEL DRUCKMAN

The premiere of Stravinsky's Le Sacre du Printemps in 1913 changed everything in Western music—and we are still, more than 90 years later, processing the fallout. Perhaps one of the most radical aspects of the piece was the primacy of rhythm. At several moments, and especially in the final "Danse Sacrale," the music is stripped to its barest elements. Harmony is static; melody is reduced to a few repetitive fragments; orchestration is unvaried. The rhythm takes center stage and is the sole musical focus at the conclusion of this epic work. All composers since have been forced to confront Sacre and the changes it ushered in—whether to embrace and expand upon or ignore them. For many, I believe, Sacre's lasting legacy was a license to use rhythm as a primary and unifying element of musical composition.

Part III of Steve Reich's Drumming (which the Juilliard Percussion Ensemble presented in its entirety for Eliot Feld's new ballet Sir Isaac's Apples in September) will be featured in the February percussion concert. (Photo by Hiroyuki Ito)

This month the Juilliard Percussion Ensemble will present a concert titled Rhythm and Process, exploring five very different works. The one common thread in all is the primacy of rhythm—not as details or colors, but the essential focal point of the music itself.

Wolfgang Rihm is one of Germany's foremost and most prolific composers. Tutuguri VI is one of a group of six pieces extracted from his ballet Tutuguri, based on an autobiographical poem by the French playwright and poet Antonin Artaud. In this work Artaud, who struggled with mental illness throughout his life and was institutionalized on many occasions, describes the psychic ordeal and spiritual revelation of his visit in 1936 to the Tarahumara Indians of Mexico. He sought them out to witness the Tutuguri, or Rite of the Black Sun, an ancient cult ceremony celebrating the glory of the sun-god with sorcerers, animal sacrifices, and peyote-induced hallucinations. Rihm was immediately struck by the inherent musicality of Artaud's writing, and has created a work of bold originality and visceral power in response.

Steve Reich's Drumming is one of the seminal works of the second half of the 20th century. It was presented at Juilliard with choreography by Eliot Feld earlier this season; for this concert, we will reprise Part III of Drumming, scored for three glockenspiels, piccolo, and whistler. The entire work is based on one 12-beat rhythmic pattern, and the gradual process of substituting notes for rests (creating more elaborate patterns) and the subsequent reduction of notes back to rests. The central rhythmic device here is phasing, where two or three identical instruments playing the same repeating melodic pattern gradually move out of synchronization with each other. The voice and piccolo gently emphasize the various "resultant patterns" generated by the pulsing of the glockenspiels.

Per Norgard is perhaps the best-known living Danish composer. After an early period strongly influenced by the Nordic traditions of Sibelius and Holmboe, he began to explore more modernist concepts such as collage and serial techniques in the 1960s. During this period he refined his "infinity series," a melodic structural principle which allows a small melodic cell consisting of a single interval to expand into an organic, self-perpetuating infinite series. He later expanded this concept to include organizational principles for rhythm and harmony as well, with inspiration in each case coming from the world of nature. In Square and Round (1985) Norgard uses an infinity series limited to two notes (bright and dark), which lends itself well to creating rhythmic structures. In the second movement, the ensemble is split into two groups playing in the same tempo but with different bar lines and phrase groupings, creating a tightly controlled rhythmic polyphony.

Juilliard Percussion Ensemble: Rhythm and Process Alice Tully Hall Monday, Feb. 13, 8 p.m. Free tickets available in the Juilliard Box Office.

Rolf Wallin, born in 1957 in Oslo, is one of Norway's most important young composers. He began his composing career while performing in experimental jazz and rock groups, and these diverse musical and aesthetic influences are clearly present in his work. His music walks a thin line between an expressive, intuitive, sometimes jazz-inflected lyricism and a more rigorous, formal modernism. Stonewave (1990-91), like Norgard's Square and Round, was written for the Swedish percussion ensemble Kroumata. As with several of his other works, Stonewave uses mathematical formulas based on fractals to generate rhythmic content. The piece is in three movements (played without pause) and is scored for six percussionists playing exclusively non-pitched instruments. Although timbral groups are specified (wood, metal, skin) the exact choices of instruments are left to the performer.

Lukas Ligeti is active in a wide variety of areas including composing for orchestras, ensembles, and soloists; playing drums in improvised and jazz settings; performing solo on electronics; and collaborating with musicians from non-Western traditions. His music has been commissioned and/or performed by the Kronos Quartet, Ensemble Modern, Orchestre National de Lyon, the Vienna Festwochen, New York University, the American Composers Forum, and many others. His Pattern Transformation for four players on two marimbas (1988) is inspired by traditional court music from the kingdom of Buganda, in what is today Uganda. The composer writes, "In this style, performed on the 'amadinda' and other xylophones, musicians play interlocking melodic patterns at very high speeds. The listener perceives melodic figures that are not present in any one player's part, but result from the combination of the interlocking lines. The pulse is so fast that it's impossible to consider any part as syncopated; each player feels the beat in a different place, and it is this relative view of the beat that renders the music playable."

Daniel Druckman, a percussion faculty member since 1991, directs the Juilliard Percussion Ensemble.