Been in travail over building a closet outside the s'hanger for the dust collector (and loose the drive through shed roof down the side) or build a closet inside. Having studied the left hand inlet on the DC for awhile, I've about made up my mind to give up the floor and locate the DC closet inside the s'hanger (shop) and vent outside with a capability to bifurcate the exhaust and use damper(s) for a filter return should the sky lights not heat the floor space in the winter - they sure do in the summer.
After the move we have plethora of flattened cardboard boxes. Some light weight and some quality, heavy Uline boxes. All sizes including wardrobes. If I double stud the closet, would repurposing the cardboard weaving it between the two sets of studs provide any noise abatement? Compared to batt insulation, better or worse? Any one have first hand experience?
And I'm not above re-visiting an outside closet, but I do like driving through that shed roof portion with truck or tractor without dodging impediments. The shed is about 10 wide, runs the full 40' of the building, and is 11' on the high side against the s'hanger with maybe a 2' drop to the open side. Pouring a 4' X 8' pad parallel to the shed and spacing it out from the building takes away that drive through capability. FWIW, I can only access the shed at each end due to grading along the outside open wall, about a 2' drop into the shed at one end and tapers to 0 at the other end (grass taxi way, fyi).
I'll be listening.