BANGOR — A committee consisting of residents and city officials and staff continued their work Tuesday night to come up with solutions to the ongoing conflict between those who see concerts on the waterfront as a needed economic boost and those who think the concerts are too loud, including all but one of the nine residents who turned up at City Hall for the meeting.

It’s a debate that has raged since the Waterfront Concert Series began holding concerts on the Bangor side of Penobscot River three years ago. But while the noise complaints continue to come in, the sound levels do not exceed noise limits set by state regulators.

Led by resident Sheila Pechinski, a University of Maine business professor, the Waterfront Sound Committee was appointed by the City Council in response to noise complaints from residents of Bangor and beyond.

During a two-hour videoconference Tuesday night, Benjamin Markham of Acentech, the Cambridge, Mass.-based consulting firm that conducted a sound study in Bangor last year, discussed some of the sound mitigating options available to the city and Waterfront Concert Series.

Acentech’s finding for the 2012 concert season led to some of the changes concertgoers saw at the venue this year, including the reorientation of the stage in an attempt to minimize noise impacts on those who live nearby.

“Our research at [Chastain Park Amphitheatre in Atlanta, Ga.] and elsewhere suggests that community response in general is quite well correlated to low-frequency sound. It tends to be the base and the boominess that generate the most complaints,” Markham said. “And that’s important in the context of a discussion of sound barriers and other structural changes because barriers are effective differently at different frequencies.”

While he didn’t want to dwell on the technical aspect, Markham said it’s substantially easier to block and redirect sound at mid and high frequencies than it is at low frequencies.

Some noise mitigating options Markham described were:

— Fencing, which would help contain high and medium frequency sound, which travels in a “line of sight” fashion. Because of the topography around the waterfront and the buildings that overlook it, such a barrier would have to be tall, Markham noted. This could block views to the river, however.

— A roofed structure could help contain sound to the waterfront but would pose similar aesthetic problems, he said.

— Turning down the volume — especially the difficult-to-contain low-frequency sound — would have an immediate effect. That could, however, have an adverse effect on concertgoers’ ”rock ‘n roll experience.”

Markham, however, noted that if Bangor imposed too many restrictions performers will no longer want to come here.

Waterfront Concert Series promoter Alex Gray agreed.

When asked for his thoughts on solutions, Gray said he earlier told city officials that the roofed structure “is the magic bullet. That being said, the views to the river are of the utmost importance. Remember that a roofed structure is going to be incredibly tall. Unless you go through it to get to the river, your view is going to be impeded at several points.”

The group’s deadline for a preliminary report to the City Council is Oct. 23, at which time the committee and council will hold a joint workshop. The committee’s final report to the council is due on Oct. 30.