A loud quarrel broke out in the front row early in the first public concert of Musica Aperta (Open Music) on Monday night in the Shakespeare Theatre. A rather aggressive man ejected the woman who was sitting there, although there were empty seats on both sides of her. She walked off, protesting that "the show's already started," and took a seat on the stage.

They were, of course, both members of the imaginative young company, which includes a string quartet, pianist, clarinetist, two singers, two dancers, an actor and a chef who fed the audience tidbits in the lobby during intermission, while the musicians played waltzes and the patrons danced and quaffed champagne.

There was also music, Renaissance and modern. Soprano Lorena Guillen opened the program with a polished performance of Kurt Weill's French cabaret song, "Youkali," a study in idealism and disillusion. She followed with excerpts from Arnold Schoenberg's "Pierrot Lunaire," showing total mastery of the difficult Sprechtstimme style. Her cell phone rang onstage; she answered it and broke into an excerpt from Poulenc's opera "La Voix Humaine," which stars a despairing soprano and a telephone, and hurried offstage to finish the call in private.

Clearly, in a Musica Aperta program, surprises (orchestrated by writer Juan Uriagereka and stage director Joe Banno) are as crucial as the music, chosen and sometimes arranged by music director Mariano Vales. "Expect the unexpected," warns an introduction in the colorful program (which includes texts of all the vocal music), and the program keeps that promise.

The music included, besides the items mentioned earlier and a piano interlude, music of Anton Webern, from his Brahms-influenced youth and his atonal, enigmatic maturity; Monteverdi's "Il Combattimento di Tancredi e Clorinda"; Shostakovich's war-haunted Quartet No. 8, with interpretive dancing; an improvised percussion piece; and a madrigal with text by Michelangelo. Gourmet fare, all very rare and well done.

-- Joseph McLellan