Indoors Out Chicago will soon have two new performance venues and a park to go with them. The 24.6-acre Millennium Park, adjacent to Grant Park, will open this spring in the downtown area that Windy City natives call the Loop. One theatre is underground, the other outdoors, and they connect with a common loading dock, dressing rooms, and other support areas. Designed by Hammond Beeby Rupert Ainge, the new Music and Dance Theatre is a box without windows, below the park and the water table. A glass greenhouse pavilion entrance stands 40' high, housing a cafe and the box office. City prohibitions against park buildings, which grew out of century-old lawsuits, held. "The structure got pushed down 35' so we could put the park on top of it," says Ed Uhlir, park project director. Lit at night, the building is transparent, "a non-building," through which passersby can see the landscape beyond.

The exterior of the adjacent Music Pavilion wraps the stage. Craig Webb, pavilion designer for Frank O. Gehry and Associates, says Gehry wanted to create "the feeling of a space shared with performers" in a venue that seats 4,000 with a lawn for some 6,000 more. Gehry, who designed the Hollywood Bowl, believes it's critical to give a strong presence to an orchestra so separated from spectators. "We started working on a bandshell with curved stainless-steel elements which would surround the concert enclosure," Webb says. They also wanted to place the shell in its urban context; Webb says Gehry sees the curves as petals, "a bouquet of flowers in the park."

Much of the lawn and stage design emerged because the Gehry firm faced a "forest of poles" that marred the landscape when it became involved. Before then, the Talaske Group, Inc. (Tgi) was busy creating the sound of a concert hall in the park. "When you go to an indoor concert to hear a symphony orchestra play, you feel enveloped in the reverberation from the side walls, ceilings, and floor," explains Jonathan Laney, senior audio consultant at Tgi. Most outdoor venues offer sound reinforcement for clarity and loudness. To this, Laney added an acoustic enhancement system to provide virtual walls. The system also masks peripheral city noise.

Laney planned to place speakers every 60' over the lawn audience, each ring consisting of both enhancement and reinforcement speakers. Lateral speakers supplement along the perimeter, firing toward the center to provide wall-like reflections. Sound also goes out to what Laney calls the "lobby," the park beyond the lawn, and sound comes back to the performers. A computerized delay system synchronizes sound from different locations at fractionally different intervals. "You wouldn't want to listen to the enhancement system by itself," Laney explains. "You would just hear reflections of a hall without the orchestra."

Tgi would bring the inside out, but where would all those speakers go in a city that wouldn't allow so much as a visible building? An initial plan to hang speakers from poles would lead to obstructed sightlines and hide the skyline.

Enter the Gehry people, who designed a trellis to span the entire 600' length and 300' width of the lawn. Made of stainless-steel pipe, 15' in diameter, and spaced 65' apart, it masks speakers and hides fixtures that light the perimeter walkway and those that serve as houselights.

A permanent system will throw color washes onto the stainless steel, which theatre consultants/lighting designers Schuler & Shook will program in collaboration with Gehry to create a slowly changing rainbow of colors. Positions have been spotted for large-scale video projectors, which can be rented.

The Grant Park Symphony will give free summer concerts in the space regularly, but pop groups will also use it occasionally, and a large screen can go in for movies. Glass doors close off the outdoor stage, which can be heated or air-conditioned, and can contain smaller performances in the winter. The stage is accessible via ramps, making it adaptable for dinner parties or events such as high school graduations, when those in the house want to interact with those onstage. And the lawn is deliberately not raked, to allow for parties and other programs.

"When you're two football fields back, sightlines are not that important," Uhlir notes. Skidmore, Owings & Merrill, coordinating architect, is charged with blending a formal Beaux-Arts setting with traditional and contemporary pieces. While O'Donnell, Wickland, Pigozzi and Peterson restored a peristyle, a semicircle of classical columns, Anish Kapoor created an elliptical sculpture, 60' long and 30' high, of polished stainless steel that reflects the landscape and the Chicago skyline. Jaume Plensa designed a modern fountain. And Gehry imagined a pedestrian bridge linking the parks.

There was some concern that the blend of contemporary and traditional would clash, but Uhlir says the lawn helps create a transition; it ends in a formal garden designed to blend with the Art Institute across the street. On the other side, the transparent building is simple and "meets the city grid in a formal way, so there is no incompatibility or tension."