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The weight of this glass makes it a more effective reflector at low frequencies, improving the hall's sonic warmth. New blackout blinds and translucent acoustic banners were installed as well. The access doors for these banners were shaped to eliminate parallel surfaces and improve clarity. The blinds and banners are housed in the wall cavities previously occupied by noisy radiators beneath the windows.

The new chiller and primary air handling units were placed in a mechanical room built into an alley to the side of the recital hall stage. This addition is structurally isolated from the rest of the building, protecting the recital hall from the low-frequency vibration generated by large mechanical equipment.

To supply conditioned air nearly silently to the recital hall, an existing fresh-air plenum beneath the hall was expanded and connected to the air handling units. Additional holes were made into the plenum to ensure slow and even airflow throughout the seating area. The air enters the hall at very low velocity through openings beneath the seats and through a supply grille at the stage front.

Air is drawn out through existing plaster grilles in the ceiling of the hall; new holes concealed by dropped plaques ensure that there is sufficient cross-sectional area for slow, quiet air return. The resulting background noise is virtually inaudible.

A sound system using beam-steered line-arrays, enabling clear, amplified speech and support for jazz music, is concealed in the pilasters flanking the proscenium. Customized subwoofers fit in the tight spaces behind the main loudspeakers.

Separating the Boom from the Box

The loudest new rooms — the practice rooms and electronic music suite — are located in the basement. The administrative offices, lobby, box office, and dressing rooms on the ground floor serve as an acoustic buffer for the recital hall.

All practice rooms include a system of sliding glass-fiber panels that can be adjusted for individual acoustical needs. Floors are resiliently mounted and ceilings resiliently hung to produce "box-in-box" constructions. Further isolation for the practice rooms, electronic music suite, and recording suite is achieved with double-stud walls and multiple layers of gypsum board. The recording suite is on the ground floor, necessarily close to the recital hall stage.

For most of the building, air supply is provided by variable air volume (VAV) boxes with silencers and duct lining. This treatment reduces background noise to acceptable levels. In the basement, VAV boxes and ducts run through corridors only so that practice rooms can have high ceilings and low noise levels.

The result is a more comfortable music building that supports new technologies while preserving the building's original acoustical and architectural character. The improvements are reportedly appreciated by both audiences and performers. In the words of guitarist Sharon Isbin, who performed at one of the opening concerts, "What was a treasure has been turned into a diamond."

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The old windows of the Morse Recital Hall, Yale University, were acoustically treated with laminated glass above and blackout blinds below. Photo: Kirkegaard Associates Control booth at the back of Morse Recital Hall. Photo: Kirkegaard Associates Sprague Memorial Hall Building Section looking south. The floors are acoustically separated, and the space between them used as an air-distribution plenum. Image: Kuwabara Payne McKenna Blumberg Architects The blackout blinds and acoustic banners are stored in a cavity once occupied by radiators. Photo: Kirkegaard Associates The banner/blind access doors. Photo: Kirkegaard Associates Detail of the shade pocketing/ window sill at Morse Recital Hall. Image: Kuwabara Payne McKenna Blumberg Architects Supply air grilles under the concert hall seating. Photo: Kirkegaard Associates Dropped plaques in the ceiling conceal new return-air holes. Photo: Kirkegaard Associates   Click on thumbnail images to view full-size pictures.