Hey all, I live in a house (separate from my studio) that I rent out with 4 other guys. This is an old house with paper thin walls where everyone can hear everything going on throughout the house. So needless to say there's no privacy for experimenting with recording vocals for demos so I need a cheap simple solution to isolate vocals (inside my bedroom) so I can sing in chest voice without the house hearing me. This "booth" will just be for rough demo tracks so the internal acoustics of it doesn't need to be great, it's strictly just for isolation purposes. Construction suggestions? How much mass?