Update on my enclosure: I redid the vacuum cleaner compartment using what I had available. Couch foam cut 2 inches thick for the baffle inside the air intake, my version of MLV (aluminum flashing with rubber tape both sides) and 6 inches couch foam on top for the fun of it. Decibel reading for the vacuum now is 80 decibels down from 101 decibels. Only 21 reduction but it is at least endurable and didn't cost me any extra money. I'll still build an impeller blower and a cyclone separator because I have extra motors and a piece of 6" diameter aluminum pipe (for the impeller blades) later on when time allows. Than I'll heed Mark's advice and build an actual sound reducing enclosure without the couch foam. Couch foam is better than egg cartons but couch foam and MLV is 21 decibels better than egg cartons, or maybe the MLV is 20 decibels better than egg cartons. Anyways, using my methods only work when you can't afford the real materials and if you want real sound reduction than paying attention to Mark's comments is the way to go.