Dan Prozinski loved living with his family above his office in an old brick building at Seven Corners in Minneapolis until the bar next door introduced loud music. The bass notes boomed through two brick walls.

Now a revision of the city's noise ordinance is giving people like Prozinski some added protection against unwanted noise.

The revamped ordinance adopted last month by the City Council gives greater weight to lower sound frequencies -- those that pass more easily through buildings -- in measuring for noise violations.

It's believed to be the first noise ordinance in Minnesota that gives such added protection against bass notes. In fact, a state noise specialist said she's not aware of other Minnesota cities that regulate indoor noise.

Minneapolis previously limited the amount of unwanted noise that can intrude into a residence or office from elsewhere in the building. The revamped law now also covers noise originating outside the building. Noise from either inside or outside violates the law if it reaches 10 decibels higher than the unit's background noise during the day, or 5 decibels at night.

Outside Minneapolis, noise is generally regulated only under a state law that sets decibel limits on outdoor noise.

The revamping of the indoor noise ordinance is part of a package of noise enforcement changes sponsored by Council Member Cam Gordon, a onetime bassist who can remember his band being told to turn down the volume occasionally.

"I'm not sure everything is going to be resolved by this," said Gordon, who heard concerns about unwanted noise from the Cedar-Riverside area where bars and housing mix. Indeed, a video demonstrating the noise impacts of one Seven Corners bar on an upstairs apartment was screened for a council committee.

Noise consultant Steve Orfield said that adopting a measurement scale that better weights the penetrating bass notes is a step forward. He also applauded another refinement of the ordinance that helps to pinpoint which sound frequencies are producing violations.

But Orfield would like to see the city go further. He'd like to see a worksheet developed that would allow bars to know more specifically how much sound they could produce before the leakage outside the bar tripped enforcement.

"These guys in many cases would like to comply but there's no straightforward way for them to know what to do," he said. Bars could also help themselves by requiring bands to use a bar sound system for which maximum settings have been determined, Orfield said, rather than rely on equipment and settings overseen by sometimes hard-of-hearing musicians.

Outdoor bar music has been a problem for some downtown residents. Ray Pertinen, speaking for residents of a Hennepin Avenue apartment building, said thumping music from bars shakes windows and creates vibrations until 2 a.m.

But a year ago, a judge struck down a separate city ordinance prohibiting music from bars from disturbing residents as too vague. That helped to stimulate the noise ordinance revisions, which repeal that old standard.

In Prozinski's case, the bar music seeping into his live-work space began about six years ago, hitting his daughter's bedroom worst and interfering with his hobby of playing and recording music.

Bar owner Bill Murray said he's tried to work out differences and even asked city monitors to check sound levels, but that Prozinski was uncooperative. Prozinski denies that. Murray has scaled back the frequency of music at his bar.

Prozinski said he loves living in Seven Corners, and accepts ambulance sirens and loud motorcycles outside his window as part of the ambience. But sustained booming music is hard to take, he said. He likens letting noise spill outside a bar to a person throwing trash on his neighbor's property.

Dan Huff, a city environmental supervisor, said the new standards won't be employed initially with the intention of shutting down bars, but rather will be used to encourage owners to find and avoid the frequencies that violate the ordinance. But uncooperative owners drawing repeated complaints will face enforcement measurements, although those are labor-intensive and require late-night hours.

"Fortunately, I have a young inspector," Huff said.

Steve Brandt • 612-673-4438