When you talk about absorbers, do you think about that? (wooden frame with semi-rigid rockwool inside?)gullfo wrote:in general, foam is limited in it's range of frequencies it will absorb effectively. if you can building 3-4" (75-100mm) thick semi-rigid insulation type absorbers for the doors, and at each end of the stair case, plus two more on the ceiling above stairs if you have the head room.
If so, it is my understanding that they are most effective when they are not directly attached to the door/wall, but there is a slight air gap behind them.
For those with ceilings, no worries:
For the doors I have seen this:
But at the limit I thought more about gluing the wood cleats directly on the door, fill with rock wool, and fix a wooden plank to the dimensions and cover with fabric.
Please excuse me for insisting but do you think that the wall is too thin and that I should make an absorber again as I was advised? (about 15cm thick)
Thank you very much