A sharply divided crowd of more than 75 people turned out for a public hearing Thursday on Merriweather Post Pavilion's request for a 30-minute extension to the state daytime noise level limit so that concerts can be held until 10:30 p.m.

Permission is critical to the future of the pavilion, said General Manager Jean Parker. "If we don't get this variance we will close our doors this season," she said. "We aren't asking to play any louder or any longer. We want to operate within the law, but that almost half of the {55} performers who played last year said they wouldn't return to the pavilion because of the restrictions."

The noise generated by concerts at Merriweather has been a constant source of debate, often pitting neighbors against each other as some Columbians argue that the pavilion is an important drawing card for the community, while others assert that it was never meant to host loud rock concerts.

State law requires that noise levels be reduced from 65 to 55 decibels after 10 p.m.

But the issue this year has reached a new threshold as the pavilion managers threaten to close the facility because of the time constraints, which they argue are limiting the number of performers they can attract.

Nonetheless, opponents of the measure, including County Executive Elizabeth Bobo, argue that the pavilion's neighbors already are suffering with the noise and that any extension would be a nuisance.

Steve Boyd, a member of Citizens Against Loud Music at Merriweather, said the music is more than "background noise. It's noise at all hours, booming bass guitars that penetrate walls." He added that people "in residential areas are entitled to quiet after 10 p.m."

Another critic of the extension, Philip Tierney, vice chairman of the Wilde Lake Village Board, said that the concerts sound like "boom boxes in our front yards."

Supporters of the extension cited the pavilion's importance to the county's economy as one of Howard's main tourist attractions. Others noted that the pavilion provides summer jobs for teen-agers and bolsters business at Columbia restaurants.

"Merriweather is our home team. It frightens me that people are against something as valuable to Columbia as Merriweather," said resident Roger Kaplan.

Some neighboring residents even said they enjoyed the free evening concerts they could listen to from their porches. "Merriweather has been a good neighbor," said Peter Driscoll, who lives a quarter-mile from the pavilion. "I'd like to hear the music louder and longer."

The latest noise problems began last summer when the pavilion was cited with a violation after state inspectors found that noise levels were too high at the nearby Southgate Apartment complex completed last year. It is the closest residential complex to the 10-acre concert site.

Merriweather officials protested the citation. "We don't want to be punished because the apartments keep coming closer and closer," Parker said.

The pavilion hired an audio consultant to study ways to reduce the noise in the neighboring areas. He presented his report at the hearing last week. All the options, which included building a 58-foot wall, or a 75-foot dirt mountain, had been ruled out by pavilion management on the basis of economics or esthetics.

Parker said that ending its music by 10 p.m. is a major problem for Merriweather. The pavilion is already constrained on both ends of the concert time. The concerts can't start earlier than 7:30 p.m. because "you're cutting into rush hour then. People coming from Washington or Baltimore can't get here before then," said Parker.

Merriweather has found it difficult to get performers to return because of the unusual restrictions, she said. "They're used to playing three-hour concerts at a certain audio level and we're asking them to play a shorter amount of time at a lower level," she said.

The pavilion, owned by the Rouse Co. and operated the New York-based Nederlander Organization, has been host to concerts since 1967 when it became the summer home of the National Symphony. Two years later, the format switched to popular music and since then crowds have packed the 14,000-seat arena to hear such groups as the Grateful Dead, Jimmy Buffett, Peter, Paul and Mary and Tina Turner.

George Ferreri, director of Air Management for the Department of Environment and the case's hearing officer, refused to speculate on when he would announce his decision.

Ferreri will send his recommendation to the secretary of the environmental department, who will make the final decision.