Quiet Solution, the Sunnyvale Calif.-based maker of QuietRock soundproof drywall, has filed suit against a competitor headed by a former employee claiming patent infringement.

The suit, filed March 7 in federal district court, alleges that a company called Supress Products LLC, seeks to halt the company from making and selling products that it claims violate the patent, which was applied for in 2003 and granted just last month.

Supress Products was founded by Bruce Donaldson, a former Quiet Solution employee.

The suit also seeks unspecified damages.

QuietRock is a score-and-snap drywall that greatly reduces sound transmission from room to room when installed together with other sound isolating technologies. It is used in home theaters and entertainment rooms where sound transmission must be kept to a minimum.

"Over the past five years, we have invested an enormous amount in our intellectual property, and we are compelled to use every legal means to protect it," said Kevin Surace, president and CEO of Quiet Solution. "We pioneered the field with breakthrough technology, and customers love the benefits of our products-easy, low-cost, effective noise reduction in commercial and residential construction."

Supress Products, based in San Rafael, Calif., which lists only an 800 number that routes callers into an automated telephone system, could not be reached for comment.