No problem with testing, I just need to get a db meter first.
I am aware of the volume of the matterial. This however would be trouble only if I salvage them, because I will need someone with a truck to help. Otherwise, 50€ shipping and most companies dispatch a truckload. add another 20€ for the transporter guys and we are fine.
Does the "Room Within A Room" method not require vacuum between the walls?
In any case, it is probably a little too extreme. My biggest concern is that the gap will be crawling with cockroaches within a few months...
not to mention that the space will be reduced significantly.