the door to an iso booth

[genericperson]

hello everyone,

John, the new site looks great!

I have a question:

I'm in the middle of building an iso booth. My idea for the door is to have a metal door from home depot with a metal frame. then on the inside of the frame hang a second solid wood door. then on the insides of each door bolt on some drywall and get the seals good.

somebody over at gearslutz insists it needs to be two separate frames. i can't see why that's such a big deal! the rest of the structure is staggered studs with a floating floor, and the insides will be heavily damped/trapped.

what's the big deal about a couple of square feet of door? the door structure i described will weigh close to 200 pounds. i think that other person has an unhealthy obsession with sympathetic resonance. he thinks it's like king kong smashing up manhattan if you do it my way.

so what's the right answer here?

or if you have another idea.... i priced Wenger doors and Overly's, but that's getting crazy. i'm a home depot kind of person.

the reason i want the metal door is i want the metal frame, and that's how you get the metal frame the home depot way.

[builder]

Hey, in terms of isolation, I am not sure of the effect two doors on the same fram will have. But from a guy who has replaced all his crappy hollow doors with solid pine from home depot, I would think there would be a issue with the weight on the frame. Just the door has cause some of my walls to give in a litte.

Just my 2 cents..... I am sure knightfly knows the isolation problem.

Good luck

[knightfly]

If you're using staggered stud walls instead of full separate frames, there wouldn't be as much improvement using separate door frames; but generally, staggered studs beats non-staggered, and separate frames (all around) beats them both, especially for lower frequencies.

Barring that, one heavy mass (no air spaces between layers) beats lighter mass for sure; but Builder has a valid concern about the extra weight. If your frame was included with a specific door, the odds of it being strong enough for more mass are gonna be real close to zip - when's the last time you got MORE than you paid for, or for that matter even felt like you got WHAT you paid for?

Another area to watch for as far as metal frames and sound doors - hollow spaces (bad) - if this isn't already taken care of, when the frame goes in you should buy a bucket or two of Plumber's Putty, and make "ropes" of it to lay into the voids between the steel frame and your wall framing - leaving these voids will drop your iso by quite a bit, you want a solid fill that's squished out a bit, then you "finger form" the squished out part - a somewhat better way is to NOT quite fill, then caulk using acoustic-rated caulk. Bottom line is, you want NO AIR within the frame, and a hermetic seal at both sides.

Lacking a full double-framed wall/door/ceiling/floor setup, the important parts are high mass and good seals, like the ones Zero international sells... Steve