Re: Help with acoustic treatment in a small room...
At the minimum you'll want a padding under the carpet, then carpet. Look to pick up some drywall to cover the brick. If you can add two layers of drywall with some green glue in-between that would be ideal and still pretty cheap (not losing much room space). When you go to play take off couch cushions or pillows and toss them around the room to dampen the high and mids. Due to room being small all of this should cost a couple hundred dollars.