BOSTON-Before The Callithumpian Consort began to play, artistic director Stephen Drury advised the audience to sit in the middle of the orchestra section of the concert hall. There was no other way, he claimed, for them to get the full quadraphonic experience. Iannis Xenakis's "Kraanerg" was performed last Tuesday at the New England Conservatory of Music's Jordan Hall, where The Callithumpian Consort ensemble is based and where all its members are students.

The conductor gave his downbeat to a simple 4/4 time signature, but the sound that filled the room could not be made by any drumstick. The brass players blew their lips off their faces, emitting a rich gurgling bass while the flautists expelled so strongly into their instruments that their notes were hidden under the gust of air. The string players exemplified the intervals of sound between each note as they slid their fingers up and down the necks of their instruments. Underneath the chaos of the newly-invented sound, there was a surreal coherence that is only found in modern classical music.

The composition was a piece of modern classical music, characterized by strange sounds that combine in a seemingly chemical reaction to produce something never before heard. Especially novel was that the orchestra on stage was only one of three important elements.

A laptop projected a recording of a second orchestra through four enormous speakers placed around the balcony of the concert hall, thus giving rise to the "quadraphonic experience." This sound traveled around the room between speakers reminiscent of the musical interlude of Led Zeppelin's "Whole Lotta Love," in which a buzz rushes back and forth between the right and left speakers. The immense sound held the audience captive from all sides.

The third element created moments so profound that they became almost spiritual. At various points during the piece all the noise stopped, and for a few seconds the silence was so enormous that no one dared to move a muscle. It lasted just long enough that the audience began to feel like it was in a conversation in which a too-long pause becomes awkward. When the music resumed, the audience could breathe once again.

Modern classical music is difficult to understand, especially when it is polytonal, and the ear must work hard to find continuity within the bombardment of sound. The audience must forget its preconceived notion that all music must have a melody in order to enjoy it, because this genre focuses on the "color" of the piece, rather than on a simple, recognizable tune. "Kraanerg" certainly did not have a melody, and the pattern of sound was difficult to uncover. For this piece, unassuming elements were used to create an adventure that could only have been produced in this advanced technological era, and can only be enjoyed by people open to a completely novel musical experience.

For a schedule of concerts at the New England Conservatory please visit: http://www.newenglandconservatory.edu/concerts/