dust collector

[cbg]

I am setting up a woodworking shop in my garage, and would like to soundproof the dust collection unit.  It's essentially a big vacuum run by a very noisy (85 db) motor.  My plan is to build, behind the garage, a separate enclosure to house the dust collector.  The enclosure will need to be at least 3'w x 2'd x 6'h.  There will be a 5" pvc pipe running from the garage to the enclosure.  I will need to vent air from the enclosure (the vacuum sucks air and wood chips from the machines in the garage and into a device that separates the chips and filters dust, and then the filtered air is vented either back into the garage or outdoors).  The outside surface of the enclosure will need to be wood clapboard to match the garage, but other than that I am free to use whatever materials I like. 

Any suggestions?

[whatismisophonia]

i dont think he's around to clarify; it sounds like he's.... well, building an external enclosure addon for his vacuum.  I'd double wall it, since it wouldnt take that much wood for such a small structure, and just use double osb on the interior.  The big trick would be the sound that comes out of the exhaust piping, whether it exits outside the house, or inside the garage.  If the soundproofing is for the benefit of the neighbors, make it exit inside the garage.  If its for the carpenter inside, make it exit outdoors.  Finally, if its for the benefit of the house attached to the garage, it should exit outside as well.  The structure should be insulated, and heating may be an issue if its not good for the thing to be in freezing temps(where does this guy live?); but that's about all i know.