How did an oratorio become Washington's musical equivalent of theater-in-the-round? Why, for the Paul Hill Chorale's annual capacity crowd, is enjoyment of Handel's "Messiah" incomplete without the audience's own vocal talents? What is it about Handel's pastiche of Old Testament texts and theatrical garnishes that incites people to command Concert Hall row-mates to "guard this seat with your life"?

Each year, the Kennedy Center is transformed into something resembling a Metro station, with thousands clustering in the Grand Foyer in hopes of squeezing in. Perhaps it's the "Messiah's" constant melody and sturdy rhythms that invite participation. At cadence points, Handel drops into the same formula, regardless of the preceding theme, contributing to the certainty of knowing where one stands in the music. Handel gives his singers expectation, not surprise.

But while the apparent ease of the music or the direct sentiments expressed in "Glory to God" may instill confidence in the amateur, the "Messiah" is not so easy to sing. There are fancy coloratura passages, fast 16th-note runs and tricky entrances everywhere. Paul Hill does not designate separate sections for the audience. Although this averts a possible crowd-control nightmare, the intermingled forces complicate the work of his audience participants. But Sunday night, it was hard not to believe Paul Hill's claim that "the audience has been getting better and better." With his system of cues, performed with three-dimensional movements throughout "His Yoke Is Easy," guest conductor Martin J. Piecuch added a third element -- dance -- to music and theater-in-the-round.

The soloists were arresting but inconsistent in their work. Soprano Margaret Genovesse had beautiful tone, but her phrasing and intonation were insecure. Tenor Christopher Petruccelli was lyrical but changed style suddenly in midphrase. Alto Valerie Eichelberger and bass David Brundage brought nobility and energy to their parts.

Unique among classical war horses, the "Messiah" enjoys a dual tradition. At the very moment that thousands lifted their voices in the "Hallelujah!," thousands of CD-shoppers nationwide perused racks of meticulously reconstructed, authentic-instrument "Messiahs." Both "Messiah" traditions need each other. Just as early-music people sometimes fall short on the work's spontaneous joy, modern choruses often fall short on accuracy. Paul Hill could easily deploy his modern personnel to create an effect closer to the one Handel wanted. More balance between strings and winds is a must.