So my booth interior is finally done and sounds great, and nice and dead. However, I haven't put any treatment on either side of either door yet mainly because I can't decide what I want on them. So far, everything is tight and quiet, but I do have some bleed that seems to be coming from right through the doors. I still have to build and extra set of seals for each door, but even still, when you put you ear up to the center of the booth door, you can hear the sound coming right through. It is HIGHLY attenuated and muffled but still pretty audible.
So I was thinking about making the outer door a sort of "super door" minus the sheet lead. But the thing is, the doors are steel so I don't know how to mount the mdf sheet to the door so the mounting screws don't spin in the metal. I don't want the thing to fall off. If I were to use Green Glue between the mdf sheet and the door, would the green glue help hold the wood in place? Or should I use construction adhesive?
Also, do you think the added weight of the mdf would cause the door to sag a bit and prevent it from closing smoothly?
Lastly, what other treatment is best to put on the outsides and between the doors? Should I just use foam? Some bass traps perhaps? Or maybe just some 2" thick broadband panels?
The doors are standard solid core pre-hung exterior doors.
External image, not preserved — original: http://i19.photobucket.com/albums/b166/djhellfire/Vocal%20Booth%20Build/Day%2033-34%20Construction/8daa15ff.jpg