do just what olde said and go grab a few pieces of plywood...corner off one of your rooms - that alone will make it so the vocals dont bounce around and give you that echo sound...then just insulate it as you can...only half of my booth is done, and i have gaping holes

right now im renting a house i'd hate to do all the work then end up wantin to move somewhere dunno i'm figure it out

as long as you dont attach the plywood to the actual foundation, then youre good...put some hinges between the pieces of plywood, and you have a foldable, moble booth