I stumbled upon this thread and thought I'd share my thoughts. I love the idea of a dedicated listening room, and your plan for the walls sounds great. For the floor, have you consider adding an additional layer of plywood with Green Glue sandwiched between them? That should help with any potential shudder.
On a side note, I'm also looking to upgrade my bonus room, and I'm thinking of adding some French doors for more natural light. I discovered doorsdirect2u.co.uk and was wondering if anyone has used them before and what their experience was like. Any feedback would be appreciated!
