Hearing is Believing: WPI Student Uses Auralization to Analyze Acoustics of Proposed Arts Center

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WORCESTER, Mass. -- WPI senior Peter De Bonte's love of science and music were in perfect harmony last spring when he analyzed ways to maximize the quality of the sounds that will emanate from the Meadow Summer Stage of the Boch Center for the Performing Arts in Mashpee, Mass. There was a touch of modern-day magic in De Bonte's "melody" - construction of this phase of the center won't begin until 1999.

A keyboardist who also plays bass guitar, has been in several Renaissance consorts, and is currently taking Middle Eastern drum lessons, De Bonte used auralization-the ability to listen to a performance space before it is built-to model the acoustics of the summer stage. The arena is part of Phase I of the Boch Center, Cape Cod's first and only year-round professional and community arts facility, which will be built on 10.9 acres adjacent to the Mashpee Commons marketplace. The 2,000-person open-air theater, the future summer home of the Boston Ballet, will include a shed similar to those at Tanglewood, Wolf Trap and Jacob's Pillow. The fan-shaped audience area will incorporate 1,000 fixed seats under a canopy covering plus space on the lawn for an additional 1,000 people. It will be adjacent to a Community Arts Center with dressing rooms and multipurpose studios for rehearsals, performances and meetings.

De Bonte examined the architectural proposal for the amphitheater, then used CATT-Acoustic (Computer-Aided Theatre Technique) software to construct a geometric model of the multifunctional outdoor space, which presented challenges different from traditional concert venues. "The walls surrounding the performance area of an indoor facility provide a sealed environment, allowing manipulation of the reflection and absorption of sound energy," says De Bonte. "Outdoor venues have no walls." Noise is another problem for the Boch Center-the windy site is a short distance from Otis Air Force Base.

In his report, De Bonte recommends adding a central loudspeaker system to make up for the area's lack of walls, grading the meadow at a steep angle, and replacing grass with ground covers such as wood chips in selected areas to improve the acoustics.

De Bonte completed his research and report for his Major Qualifying Project, a WPI degree requirement. "When I began my MQP, the CATT software did not support the correct modeling of open-air theaters," he says. "The project required creative approximation of the open-air space as an indoor facility." Bengt-Inge Dalenbäck of Chalmers University of Technology in Sweden, who wrote the software, has since released version 7, which De Bonte says may possibly be the first software tool written for geometric modeling capable of correctly dealing with open-air acoustic spaces.

"In general, the modeling process begins when you create a three-dimensional plot of the acoustic space, in this case the Boch Center's Meadow Summer Stage, on the computer and define the locations of sources (musicians) and receivers (members of the audience) within this plot," De Bonte explains. "CATT then simulates sound as rays traveling from the sources to the receivers. The path of each 'sound ray' to the ears of each audience member is almost always direct. It bounces off the walls, ceiling and other surfaces that make up the acoustic space-much like light often reflects off the many surfaces in a room before reaching one's eye.

"By analyzing such parameters as the total length of each path and the acoustic properties of the surfaces (some surfaces will reflect less sound than others, like a black wall will reflect less light than a white wall), the software is able to model what listeners will hear."

"Pete's research was limited to the shed and audience portion of the summer stage," says Richard H. Campbell, an acoustics expert and WPI adjunct professor of electric and computer engineering, who served as faculty advisor with ECE Associate Professor William R. Michalson. "He used the software in an unconventional way to construct the geometric model. Unfortunately, he ran out of time and was not able to include the tent and loudspeaker structures that are an essential part of the theater's current acoustic design. Auralizing the Meadow Summer Stage, if and when the tent and speakers are put into the model, would be a great help to the designers. Pete's MQP is a good baseline model for future studies by acoustics professionals."

"We are determined to provide superior sound quality to our audiences," says Boch Center President T.K. Thompson. "We envision the center as a national artistic and cultural haven whose offerings will include classical music, dance, opera, musical theater, drama, jazz, films and lectures. To achieve our goal, we are committed to incorporating the latest and most appropriate technology available into its design and construction. " The $16 million project, which began with seed funding from car dealer Ernie Boch, is currently in the permit process and requires an additional $3.5 million before construction of the first phase can begin. Additional information about the Boch Center is available at http://www.capecodtravel.com/boch.

The MQP is one of three projects all WPI undergraduates undertake as part of the innovative WPI Plan, a flexible and academically challenging program introduced in 1972. Under the Plan, students are provided with unique opportunities for integrating classroom studies with preprofessional academic projects conducted on campus or at companies, agencies and project sites in the U.S. and abroad. Through the MQP, students solve real-life problems in their major field of study. The goals of the MQP include the development of creativity, self-confidence, and the ability to communicate ideas.

De Bonte is the son of Patricia Lovejoy and William J. De Bonte of Lexington, Mass. He gradated from Lexington High School and transferred to WPI in 1997 after a year at Carnegie Mellon University in Pittsburgh, Pa., and two years at Landmark College in Putney, Vt. He received his bachelor's degree in electrical engineering from WPI in October and is staying on to pursue a master's degree in electrical engineering with a focus on analog microelectronics with some studies in acoustics. He has been a member of the fencing team, the Society of Medieval Arts and Sciences, the Science Fiction Society, and Eta Kappa Nu, the electrical engineering honor society. His home page may be viewed at http://www.wpi.edu/~pwd/me/academic.html.

An independent technological university founded in 1865, WPI is renowned for its project-based educational program. Under the WPI Plan, students are provided with unique opportunities to integrate classroom studies with preprofessional projects conducted on campus and at off-campus locations around the world.

WPI was ranked among the top national universities in the 1999 edition of U.S. News & World Report's Best Colleges Guide and was ranked 18th among the top national institutions in the magazine's Best College Values report.