QUIET, PLEASE: Pauline Oliveros' first step was to immerse her ragtag supergroup in silence.

SoundExchange, presented by the Philadelphia chapter of the American Composers Forum in conjunction with West Philly's Ars Nova Workshop, brings together over a dozen area musicians and composers under the tutelage of experimental music pioneer Pauline Oliveros for a two-month residency, culminating in a weekend of workshops and performances.

The program was originated in 2004 by Katy Clark, then chapter director of ACF Philadelphia, and Thaddeus Squire, artistic executive director of Peregrine Arts. At that time, the two organizations "identified that services which benefit electro-acoustic and improvisatory composers in our city were lacking," according to Jim Jordan, Clark's successor. Squire explains that SE is "designed to bring artists with very distinct approaches to contemporary practice into Philadelphia and offer a context in which they can have a deep interaction with local artists that leaves a lasting impression and influence."

Jan. 16, Philadelphia Ethical Society: The musicians gather, seated in a semicircle around the stage. Two cellos, two basses, a trumpet, laptops, tables topped with all manner of electronic doodads, wildly sprawling wires and cables. All is silent. For five minutes, the only sounds are the hum of the heating system, the rustle of clothing, the scrape of chairs on the hardwood floor. When, three minutes in, a sudden loud clank is heard from outside, a noise that would otherwise have been just another background element suddenly becomes jolting, electrifying.

Pauline Oliveros began this introductory workshop by noting with a chuckle the "interesting orchestra" assembled. Then she immersed them in silence. The reason being, as Oliveros said, "to get people listening more deeply than they realized that they could." While plenty of noise would be made and manipulated by the impromptu orchestra over the ensuing eight hours, this opening exercise is key to understanding Oliveros' concept of Deep Listening, a theory formed during her experiments with tape manipulation in the 1960s, when she wanted to "evolve my listening as part of my cultural understanding. So I try to cultivate being the sounds that I hear, so that I'm feeling them in my body and feeling as if I am the sound."

To that end, Oliveros doesn't differentiate between environmental sound and more traditional music. "People get focused in certain ways and sound goes by them and is not attended to, so there's the 'othering' of all kinds of sound as background noise or something that can be discarded. The fact is that wherever you are, whatever you're doing, there is a sonic context."

The Jan. 16 workshop was the only actual meeting between Oliveros and the group before the final concerts. In the meantime, the musicians are expected to convene and expand upon the ideas introduced that day, while the four composers develop their pieces. Oliveros was chosen, says Squire, because her work "blurs the boundaries between composition and performance"; in the same vein, the composers must decide how to balance composition and improvisation.

At rehearsal a month later, another listening exercise is interrupted by the buzzing of a cell phone — mine, I confess — set on "vibrate" but nonetheless noticeable. Initially overcome by the panic of the unintentionally rude, I recall Oliveros' Circle Trio CD, Live at the Meridian, when a ringtone, typically met with nothing but icy stares, was instead absorbed and integrated into the ongoing improvisation.

Dr. Oliveros refers to this as "playing the environment," and welcomes these intrusions. "I've played in places where there's kitchen noise and people eating noise and all of that, and I play with it. After a while it's like you have partners in making the music. You're harmonizing with the space rather than struggling against it."

After the silence exercise, Oliveros has everyone play one sound, whatever and whenever they want, within one minute. A quick electronic blurp, a long bowed string, a whimsical blast from a slide whistle. Bassist Evan Lipson simply whips his bow through the air, producing a whoosh of air. It is the improvisers' equivalent to 'Hello, My Name Is' tags.

Then again, perhaps the combination would not be as strange as it seems. During one improvisation, Sir Gerone Dale Jimenez, Esq., aka Mr. D (he insisted on the full name), strummed his guembri, a three-string African lute, as cellist Monica McIntyre bowed long drones. Jimenez sang softly, wordlessly, almost to himself, soon joined by McIntyre, a neo-soul singer in her other life, adding louder, soul-inspired melodies. The combination was unexpected and beautiful. Jimenez notes that while all improvisers have tricks they fall back on, they're unnecessary "when what is happening is true. Nothing matters when it's true. There is no individual when it's true. Just oneness. Damn, I sound like a Buddhist."

Oliveros' third exercise moves around the room, two playing as a duo, a third entering to form a trio until the first drops out, then the next in line joins, the combinations traveling like the wave at a ball game. The first remarkable moment comes as trumpeter Bart Miltenberger joins Byard Lancaster's piccolo, the two playing almost in unison until their lines diverge like unraveling threads.

While playing, Cohen is similarly unobtrusive, but adds spice like a gourmet chef, entering with just the right accents to alter the environment. Uncharacteristically, Lancaster was content to sit and watch, curious about the unfamiliar electronic instruments. "I know when a drummer's really getting down," he explained, "but here I don't know."

Feb. 16 rehearsal, Settlement Music School: Audiovisualist John J.H. Phillips has been the most hands-on of the four composers, the only one until now to have attended the weekly rehearsals. He therefore takes de facto control of the session. Still, he struggles with composing for an improvisatory unit, toying with using video images to evoke moods or ideas ("enigmatic," "flatulent") from the ensemble. But logistics interfere — how to screen the video without disengaging the musicians from the audience? Having previously collaborated on audiovisual installations involving mechanical sculptures, Phillips throws out the idea of motorized cues. "Like Fraggle Rock?" interjects bassist Joseph Whitt.

The first workshop was held on MLK Day, and en route composer/guitarist Jonathan Matis heard a radio program on Dr. King's decision to speak out against the Vietnam War. He decided to write a piece centered around King's 1967 "Beyond Vietnam" speech, with various members of the ensemble reading portions while subsets of the group play Matis' "score," denoting textures, pitches and ideas for each section.

Composer/multi-instrumentalist Valerie Opielski is particularly attracted to Oliveros' "definition of music as being much broader than the way it is normally defined." Opielski is considering creating a sound montage to play underneath the live musicians, to regulate the timing and mood, but flexible enough to allow for spontaneity.

The fourth composer, DJ and laptop artist Ben Camp, is secretive about the piece he will unveil for the performance, but hopes to combine structured composition, guided improvisation and free playing.

Both the initial workshop and later rehearsal seem tenuous, still a feeling-out process. Behind a table that looks like a flea market electronics sale, piled with a guitar and various devices for sonic manipulation, Jesse Kudler voices skepticism about playing improvisation exercises without knowing the eventual shape the compositions will take.

Essentially, this thought leads directly to Oliveros' Deep Listening concept. Via telephone from her Kingston, N.Y., home, shortly after the mid-February blizzard, she appreciated the snow-induced quietude. "But if you're someplace where there's noisy activity, there's nothing you can do about it except take yourself away. So I prefer to listen to it and embrace it and find out what I can. There's always knowledge and intelligence in sound, whatever it is."

Pauline Oliveros' Deep Listening Band plays Fri., March 31, 8 p.m., $10-$20; the SoundExchange ensemble premieres its four compositions Sun., April 2, 4 p.m., $10-$20, Trinity Center for Urban Life, 22nd and Spruce sts., www.arsnovaworkshop.com.