Hi I'm doing some research on converting my garage/basement (the house is on a hill so the back wall of the garage is essentially underground) into a rehearsal/listening/recording room. I've been looking at 3 different wall systems from British Gypsum http://www.british-gypsum.com/white-book-system-selector/systems-overview/gypwall-quiet-iwl http://www.british-gypsum.com/white-book-system-selector/systems-overview/gypwall-quiet http://www.british-gypsum.com/white-book-system-selector/systems-overview/gypwall-audio They offer different levels of sound insulation, with the downside being larger footprint and/or price. But...I'm not sure how much is enough?? The performance of the wall systems are given as airborne sound insulation and depending on the wall construction is between 61 - 80 (Rw dB). Have no idea whether 61 would be adequate or not?? Can anyone explain these numbers to me and give an example(s) of how this relates to 'real' things (i.e. the level of a guitar being strummed or something...) I'm not saying too much about the construction and layout of the garage as I really would like to get my head around what the numbers mean and then start a new thread discussing the rest.... Potential noise sources: - We are on a cul-de-sac, so there will be little traffic noise (the odd car going past at 10mph, or engine starting). I'm more concerned about weather (wind and rain noise), and noises from the adjoining garage on one side and the adjoining hallway on the other. So, people talking etc, the sound of stuff being moved around, a car pulling into the garage. - I don't want noise leaking out either. I guess this is potentially easier than most problems as we will not be using large drum kits, bass amps etc. Mainly acoustic instruments and vocals.