Iso Room Door or Doors in 12" Jamb?

New to this forum and first time post. I'm going to apologize upfront for asking what may have already been addressed. I have already spent several hours looking for answers to no avail. There is simply too much to sift through with the weak search engine I'm building an Iso Room inside my studio. One to isolate loud guitar amplifiers from the main room. It will sit on a concrete floor with double, decoupled walls and decoupled (from existing ceiling) ceiling. The decoupled walls will sit on separate plates approx 1" apart. With double 1/2" sheetrock on both the interior and exterior surfaces of the structure, this will make my jamb approx 12" deep. I haven't decided on which type of insulation to use; Rockwool, Thermafiber or Pink. I have a 36" double glass exterior door (from a remodel demo), and I plan to install a 1/2" thick sheet of glass set inside the routed stiles of the door and then overlay (sandwich) the stiles and the edges of the glass with routed MDF, using acousticaulk to seal. Suffice to say, without drawing a detailed image, this door will be solid. My question(s): Providing my jamb and threshold are sound and secure, will this be enough of a barrier for the iso room? Or, do I need to install double doors? I really don't want a door swinging into the iso room taking up space, but I will if ness. Thanks, Brett

The short answer is no. The reason is that with a decoupled wall assembly you remove the path that vibration follows that can create interference, and that makes a room that is very quiet. But in order for it to be the >most< effective there has to be a interior boundary/ with access door AND an exterior boundary/ with access door. In your situation you are going to make the "room-in-a-room assembly but then you bypass it with only one door. That allows everything that the interior solid core door >would< have stopped/slowed down, direct access to your exterior wall. So the whole iso booth is reduced to whatever isolation that one door will give you...and not much more, maybe a little, but the door is your weak spot, having nothing more to go on at the moment.

Thanks for the reply, Brien. Understood. I haven't as of yet designed the jamb. The more I thought about it this afternoon, I realized that I would need a door for each wall. Makes perfect sense. I guess I was hoping to design a jamb that would magically work for both walls. I would love to have more room by NOT having two walls and two doors. Has anyone had success with a "one wall" iso room?

You would install resilient channel on the interior side of a single framed wall, some might argue to install it on the exterior side of the wall, but in any event, this will get you the decoupling you want, not as good a TL for the overall assembly, but better than just a frame with sheetrock on either side. You would have to treat the ceiling the same way, with resilient channel to decouple.