Improve door isolation

Hi, I am currently finishing my small studio, based on a lot of principles adviced over here, in this fantastic forum. My floors are floating, my walls are very solid, I have some panel traps like Ethan's, etc. I already did some lsitening tests inside the room, and I am very happy with the sound. So far, so good. The only real problem I notice, is that my studio door seems to be a major source of sound leakage. Even though I have an airlock (and thus two doors) I find the isolation could still be improved... a lot. The only question is how I can do this without changing too much. I will post a small sketch of the layout, but what I already can tell is that the door in question is a 50mm solid wood door and that a lot of care was already taken to ensure that the sealing is done properly. But when you stand in the airlock, it seems as if the sound is still coming right through the door... even rather high frequencies are still quite audible! Now, some people already adviced me to stick something to the door, e.g. a thick layer of rockwool covered with fabric. But I have my doubts if this will work. What will it do? Will it dampen the sound coming through? Will it dampen the vibrations of the door itself? And what's the best way to do this? On the inside of the studio? In the airlock? As you can see, a lot of questions... So, all advice will be greatly appreciated. Thanks. Regards, Berre

Here's as promised a drawing of the floorplan.

Hi Berre, you say that you're not happy with isolation when standing INSIDE the airlock!Well how is it outside the SECOND door?Two doors and an air lock are supposed to "work together" to provide good isolation between the space (your studio) inside the first door (which you labeled PROBLEMATIC) and the space on the outside of the second door (which in your case i'm assuming is the outside of the building?) I think the rockwool or other absorbent would help a bit to absorb the vibrations INSIDE THE AIRLOCK...so yeah put some on both doors facing the airlock area.I guess you can put some on the other side of the STUDIO SIDE DOOR if you need more high freq. absorption :) So don't judge your isolation inside the airlock , but outside of that outter door, unless you have something important happening in the airlock area... :) And make sure both of your doors are well sealed...remember: 2 leaves of mass and an air space! cheers

Hi Sen, Thanks for the reply. Of course I know that the two doors should be working together. My idea was, however, that the better the first door isolates, the better the total isolation will be. The 2nd door is not going to outside the building but in fact to the hallway. The drawing is actually just one room of my home. So, the reason I want the isolation to be improved is to avoid excessive noise to go to the other rooms, especially the bedroom next to the studio, and the neighbours across the hallway. At this moment there's still quite some sound going into the other rooms, but actually that's mostly very low frequencies. I'm afraid my floating floor is not as good as hoped (and I think I know why, but that's too late, of course). And I know that the door won't help with that. There's just a little voice inside me saying that I should check all possible sources of leakage. But I agree, I will take another look at how good the second door is sealed when closed, and see if things can be improved there. I'll keep you posted on the results. Regards, B-)

That's good Berre, check the seals as you mentioned, consider sticking that extra absorption on the doors too.Is it at all possible to add any sort of mass to the existing doors (like a layer of mdf,plywood etc..)? How are the things in the hallway anyway?Just a little better than in the air lock or noticeably better? ....yeah let us know how it goes cheers

Hi Sen, I haven't been able to do a lot last evening. In fact, I'm afraid I won't be able to do a lot to the studio before next week... But, to answer your question: as far as I can remember, the result in the hallway is actually already quite better than in the airlock, even though the 2nd door hasn't been sealed very well yet. It's mainly the basses that are still coming through, there. Adding mass to the door seems like a good idea. I will have a look into that. I still have some MDF laying around, so maybe that will become useful now. Thanks for all the advice... Kind regards, B-)

let us know what happens :D :)