Originally Posted by corporationpaintball
You're in a basement... the ground does the sound proofing. You'll need to make sure any windows/doors are closed and covered but other than that you should be good. I would also recommend you put a CO2 detector in if you plan to have a lot of people packed into your basement. Be sure that people don't smoke either, if they burn down the building or someone gets hurt it's on you.
Was just at a party last weekend and they were letting you smoke anything you wanted to as long as it was in the basement. There were so many cigarette butts, Black and Mild filters and roaches on the ground, but the basement was concrete and pretty much a puddle from people not knowing how to fill a cup from a keg, three games of pong going on at once, flip cup, spilled drinks, etc., so it didn't really matter.
As long as it's a concrete basement I don't see the problem in letting people smoke (as long as you don't mind your house smelling like smoke and having to pick up the butts/filters/etc.).