soundproofing for urban people

I've just run across some videos from the Geek Group , and they were hard at work building a sound studio earlier in 2010. In this video, Chris describes how they affixed drywall to the original cinderblock walls of their space. I don't necessarily agree with some of their processes (didn't they read my multiple blog posts about Green Glue?), but they've been attaching wood strips to the cinderblock with glue, then adding resilient channel strips from Auralex, and then attaching drywall to the strips. However, he confesses that they're not adding insulation behind the wall because of their budget. But they were going to caulk between the pieces of drywall and add a second layer of gypsum (drywall) on top of the one you see in this video, placing the second layer in the opposite direction so that the seams don't line up. Here's the video. Not all of it is about construction -- it also covers the gear in their studio and other random stuff.  To se