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Acoustics: A new approach to amplifying live music aims to cut distortion and reverberation

Sound engineers at Bose Corp. in Framingham call it "The Problem," and they trace it back to the Beatles concert in Shea Stadium in 1965 and the Woodstock music festival in 1969.

The Beatles performance is recalled most vividly as a cultural milestone, with young American girls screaming and swooning over the British rockers, and a record-breaking crowd of 55,000 ushering in a new era of live music in giant venues. But for musicians and sound technicians, it is remembered chiefly as an acoustical fiasco. The amplifying equipment used since early in the century to project sound to ever larger audiences proved inadequate for the New York stadium, with neither the audience nor the musicians hearing much of anything.

To compensate, the music industry turned to a "triple amplification system," rolled out at Woodstock, with a back line of instrument amplifiers behind the musicians, giant PA speakers facing the audience, and monitor speakers onstage to allow the performers to hear themselves and one another. This system quickly became the standard for venues of all sizes, and it has endured for nearly 35 years. But while the music is now audible, what people often hear is garbled chords, unintelligible lyrics, and loud sounds bouncing off walls and ceilings.

Now Bose is introducing what it bills as the first big advance in amplifying live music in decades. Its new approach, unveiled last week after a 10-year research project involving engineers and musicians, uses Cylindrical Radiator loudspeakers to reduce distortion and disperse sound evenly around the stage and throughout a concert hall.

Unlike conventional loudspeakers, which send out sound in all directions, resulting in different volumes for the musicians and the audience, the new Bose speakers radiate sound outward and to the sides, but hardly at all up and down. The system aims to dramatically lessen reverberation and approximate the acoustics of traditional unamplified performance. It also seeks to restore "the cocktail party effect," the ability to identify voices and instruments coming from different directions, that is often lost to sound-mixing in the triple amplification system.

"This addresses some very serious problems that get in the way of amplified live music," said Kenneth Jacob, chief engineer of the Bose Professional Systems division, who led the live music research project. "The architecture of amplified live music has been the same since the 1960s."

Competitors dispute the notion that amplification technology has not progressed. Kenton Forsythe, a founder and executive vice president of strategic product development at Eastern Acoustical Works Inc. in Whitinsville, which sells loudspeakers for installation in churches, dance clubs and sports arenas, said his company and others have pioneered advances through digital controls that enable existing amplification systems to more precisely place sound.

Forsythe said he was unaware of Bose's new approach. "There's validity to the concept, but it's not the only way to go," he said. "They'll market it heavily and they'll get some response to it. This is better sound through marketing."

And, indeed, Bose has already begun marketing its new sound. The company's Cylindrical Radiator speakers, which are about 7 feet tall and weigh about 30 pounds each, will be sold initially to musicians but later to concert venues or subcontractors that install acoustical equipment. Bose has priced them at $1,699 apiece, plus $299 for base modules used for some instruments. At that price point, a system of four or five loudspeakers would be comparable in cost to a good-quality triple amplification system for a five-piece band, according to a Bose pricing study. While the conventional equipment would be cheaper for soloists or smaller groups, the Cylindrical Radiator speakers would be more economical for larger bands -- and less time-consuming to install.

Inside the speakers, two dozen small and powerful transducers are stacked vertically in a flagpole configuration. Each transducer, about 2 1/4 inches wide, can convert 30 watts of electrical power into sound. "So long as these transducers are all operating together as a cohesive unit, they can produce the wedge-shaped radiation pattern we want," Jacob said. "We want to squeeze the sound energy into a pancake so it can't leak out" in all directions.

Jacob said his Bose team went through seven or eight prototypes and has submitted five patents on its new technology to the US Patent Office. It also has tested its speakers at small and midsize venues, including a 400-seat theater in Arlington. In a larger venue, the Cylindrical Radiators would be effective for musicians and audience members in the front rows, but would require auxiliary amplification for the rest of the arena, he said. Bose eventually will "scale up" the speakers so they can be used in larger theaters and even stadiums, Jacob said.

How widely sound can be dispersed by Bose's new system may be the key question for musicians thinking of adopting it, said Wayne Thompson, editor of Jazz Scene, a monthly publication based in Portland, Ore. "I think it could be revolutionary for any band," Thompson said. "Bands, and jazz bands particularly, are paralyzed by the current system because they can't hear each other, and communications between them is important."

Bose executives won't disclose how much money they invested in development of the Cylindrical Research loudspeakers, a project that grew out of a conversation between Jacob and keyboard player Clifford A. Henricksen, a performing musician, nearly a decade ago. But company founder Amar G. Bose, who appeared at press briefing at which the speakers were introduced last week, said he had given Jacob the green light to go over budget.

Recalling that he founded the company in 1964 "the hard way," as a private concern, Bose, a former MIT electrical engineering professor with expertise in psychoacoustics, said "we wanted to be free to do research, something that lowers your balance sheet every year" without having to justify the outlays to Wall Street.

"There was something about this research project that really caught my attention," Bose said. "They were trying to bring the advantages of live acoustical performance of instruments to the amplified sound discipline."

Robert Weisman can be reached at

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