I would like to improve the sound quality in a room that intend to use to demonstrate amplifiers. It doesn't need to be completely sound proofed. I just want to create that 'still' studio quality. Know what I mean? What can I do relatively cheaply to create this? The room is a finished basement with concrete walls behind the finished walls. The floor already has carpet. The room already sounds good but I want it to be better. Thanks for your help.