How do I enclose my dust collector to reduce noise?

I'd like to enclose my shop's dust collector to reduce the noise it makes during use. What do I need to know before tackling this?
—Ray Crosby, Cedar City, Utah

A dust collector doesn't emit the high-pitched whine of, say, a shop vacuum, Ray, but you're not alone in being bothered by the constant noise. And it's a good idea to keep the unit running even when you're not using a dust-making machine, because the collector continues to pull dust from the air through open blast gates, (hopefully) trapping it in the filter.

But enclosing a dust collector is not as simple as just stuffing it in a closet—you need to keep a few things in mind. First, you're not building a recording studio, where all noise must be eliminated. Instead, you just need to dampen the noise to a level that's not disturbing. Second, in order to have effective airflow through your ductwork, you must allow filtered air to return to the shop, through vents in either the walls or doors. And third, you need easy access to the collection bin or bags for dumping and cleaning.

Dust collectors often fit conveniently into corners, so adding a two-sided enclosure is a simple way to start. You can make your enclosure permanent, or hinge two wall panels together for a freestanding, removable solution. Lining the inside of the enclosure with rigid foamboard or "egg-crate" acoustic foam will further deaden noise. But remember, walling off a noisy dust collector also puts the chip bin out of sight, so don't forget to check the fill level frequently.