The first thing to go up is the dividing wall – the one-block high line that Jeff’s building at the moment. This is at a slight angle for acoustic reasons, and also to make the control room slightly wider than the live room. The cement mixer here is roughly where the drum kit will be. The main wall in the middle will eventually come down and be replaced by the new one.
In the picture above you can see where the glass wall is going to be. Both rooms will be sealed boxes, and this wall of concrete blocks will provide mass for (mostly low-frequency) absorption between rooms. The physics is all based around the principle that sound travels least well when it has to get through varying densities. So the dividing wall will have a sealed box, then an air gap, then a large mass (these concrete blocks) then another air gap, then another sealed box.
To show the principle further, here (on the right) is one of Howard’s close-up discussion diagrams for the floor, using concrete (floor) ‘jablite‘ (insulation), 2 x ply (flooring) and rubber-backed carpet (click on the image for a larger version).
And here’s the plan – live room shown here on the right of the picture; this shows the angled wall and window position more clearly.