Why do I have double drywall in ONE wall?

[tullemannen]

For soundproof walls to be effective, they should be sound-rated, or at least a solid door and soundproof over-air vent should be used.

We invested in solid doors during the new build, but were unfortunately disappointed, not primarily because of the doors. The gap between the door and the threshold, which exists due to ventilation flow, leaks an awful lot of noise. It's difficult to get around this issue, unfortunately.

 

[mycke_nu]

Never heard of this. It's a bit hard to see on the innermost board, but the one closest to the cameraman seems to build a lot down into the room. Won't there be very wavy ceiling moldings if you choose to do this?
Edit: I see that the closest board is not screwed yet. But still, won't it be wavy?

No, it will be smooth and nice. A plasterboard doesn't bend that easily.

 

[Mikael_L]

We opted for massive doors in the new build, but unfortunately were disappointed, not primarily because of the doors. The gap between the door and threshold that exists due to ventilation flow leaks an awful lot of sound. Difficult to get around that problem unfortunately.

Not so difficult really, but it requires more complex construction. The recipe is: A heavy sealed door with a higher sound class. Sealed around the frame and threshold with a rubber strip. Ventilation via soundproofed air transfer unit or both supply and exhaust air in the room with sound dampers in the ducts.