Hello again. Ok, thanks for the info. Still need some more.
Do you have a lease on this space, and if so, for how long?
Is the metal door removable?
What are the ceilings made of and if there is a dropped false finish ceiling, can you see into this space between the finish cieling and the bottom of the floor above?
What type of HVAC exists? I assume from the "hiss" noise, there are existing registers/ducts. Where are these in relationship to the vault? Is there a supply and return register/grill? Are the ducts in the void between a finish ceiling and the floor above? Does the HVAC supply the space above too? Or any other space? Are any of the ducts supplying or returning air to your space as well as others, or are there seperate ducts for each space?
I assume the wall seperating the vault from the control room is concrete, no?
How thick is this wall, and how far from the duct work is it?
Given the fact that your main room is only 14' x 22', this vault represents valuable square footage

and I would use it if ventilation can be installed. Either via a seperate fan unit installed somewhere else, or tieing into the existing ducts, with serpintine ductwork. Especially given the fact this is already concrete, I believe you can cheaply build a floating booth within this space, IF you can remove the existing metal door. Does this landlord want you to keep this assembly INTACT? Perhaps, you can remove the whole
assembly, although it may not be easy, but I've done worse. I use to have a shop in an old dairy with 14" thick concrete walls that I cut a doorway into. Took 2 days. Once framed in, the doors looked great. Maybe you could remove the whole jamb and widen the door?
To my way of thinking, FIVE THOUSAND DOLLARS is a LOT of money.
If it were me, I would make this work no matter what. Treatment is worthless if you can't breath, or if you have to open the door constantly to let fresh air in, as even a small incandescent bulb will raise the temperature fairly quickly. Treatment is still insulation, so a small space will hold this heat in. Even one person breathing, can quickly deplete the freshness of the existing air. Like I said, once you soundproof, you airproof. So checkout EVERYTHING you can regarding the existing HVAC. Is this room COMPLETELY below ground, or is it partially above ground, and are any walls exterior? I'm looking for avenues to vent or alternatives. Thats what you have to do, is look at ALL the alternatives, which translate into knowing what is there. The first thing you have to solve is ventilation, so let us know and we will try to go from there.
fitZ
