This short video from builder Matt Risinger covers a lot of the issues we've discussed in this soundproofing blog. Matt has a show on YouTube that gives examples of successful construction projects. In this example, he shows a soundproofing project in a two-unit condo with a shared wall between them. They did everything right. The used staggered wall studs (with an 8-inch separation between the two units), Roxul batting, QuietRock on the walls, putty pads on the outlets, and Green Glue . As a test, Matt turns on a boom box in one of the rooms and measures the decibel output. Then he goes to the room on the other side of the wall to show how much of that noise leaks through and uses a decibel meter again. It's almost silent. This is what you hope to achieve, especially with new construction. But it won't happen unless you use the type of materials and processes shown here. Here's the video. Great job!