Hi I am having the same problem. I am also in a band and I am trying to sound proof my basement as cheap as possible. What I can tell you is the egg carton idea is a myth and really dosen't do anything. Apparently drywall is a fairly good sound block. If you have any ideas I'd love to hear them. Every site I find on sound proofing the ideas cost thousands of dollars and require alot of work. There has to be a easier way.