Home theater safe room - IB setup

[srimes]

Hi y'all, this is my first post.

I'll be moving to Tulsa, Ok next month. They have a lot of tornados there, which my wife is very scared of, so we'll be building a concrete above ground safe room, which I want to turn into a home theater. We haven't decided on a design yet, but I'm thinking it'll be about 10' x 12', and I like the idea of insulated concrete forms (ICF), which should be nice and quiet.

I'd like to plan for the IB setup from he start, as that should be easier than cutting a hole in the solid wall later. But it still needs to be a safe room. Maybe vent down through the slab floor and over and up. That vent would be concrete/metal, so would it sound bad?

Anyone have experience with this type of setup? How big of a vent should I plan for? We'll be borrowing money to build the room, so the IB setup will be pretty basic by the standards of this board. Which is still a ton better that the "home theater" systems most people get from best buy.

Thanks,
Sean

[inm8]

Hey, thats not a bad idea at all. At least you'll have something to cheer you up when the tornados comes ;D

Given that it is to be a safe room however, there are a few extra considerations. As you would have read, an IB needs quite a large area to vent into. In your case, this probably means that you are going to need a seperate chamber within the safe room itself for the backwave. If you're rear volume is too small, you will end up with a larged sealed sub, rather than an IB.

Rather then compromising the structure of the safe house itself by cutting into the concrete forms, I would reccomend that you build a seperate chamber within the room (probably up the front) which could just be a plain stud/gyprock wall with an IB array/manifold mounted. If you wanted, this could also accomodate for a shadow box (if you are getting a projector) and equipment/storage for other items.

Also, you may want to look at room treatment to cut down on early reflections and lower the reverb time. 4" fibreglass mounted strategically with 1" spacing is excellent for this, and it's not too expensive either.

btw: You can work out exactly how much volume iyou need for the backwave using the guide in the FAQ.

[chrisbee]

I'd be finding somewhere to live and work as far from Tulsa as my skills, qualifications and ambitions allowed.

[ThomasW]

Safe rooms as I understand them have rather massive doors that seal the entrance. The same construction would be needed to close off the opening of a manifold into the room to guarantee the room's integrity during an emergency.

I hate to say this but 10'X12' is really too small for a HT....

[srimes]

What is the minimum size for a HT, and why ? I don't think I'd need to seat more than 6 at the most.

I was thinking that the IB would vent to the outside somehow, yet still be "safe." Maybe covered with expanded steel plate or an offset wall so the debris doesn't have a straight shot.

[ThomasW]

srimes said:

What is the minimum size for a HT, and why ? I don't think I'd need to seat more than 6 at the most.

Unless you're planning on custom built speakers (without baffle-step compensation) the main and center speakers should be 2' from any boundary.

The listeners/viewers should be the appropriate distance from the screen depending on it's size.

It's a good idea to have an open area behind the listeners/viewers so the soundwave off the mains is absorbed/diffused.

All this means the seating positions should have plenty of breathing space on all around, so no backs or arms of chairs against any wall. Yes the seats can be clustered together, but the cluster itself should have open space on all 4 sides

When possible it's best to have "Golden Mean" or "Golden Rectangle" room proportions to optomize audio reproduction.

Doing all the above for 6 people in a 10'X12' would be basically impossible.

My suggestion is to find a book on HT design. Sorry but I don't know a specific one, my knowledge of this is based on lessons learned designing and building A/V rooms since 1982.

[srimes]

Well, the room isn't built yet, so if I can afford it it can be bigger. I'm thinking just 2 3-person couches would be plenty, and if we can't afford to build something that big then 1 couch would be OK. Also, if it isn't feasible to vent the IB to the outside it could be vented to the 3/4 bath that will be built into the safe room as well.

[txsmoke]

Look here www.fema.gov/plan/prevent/saferoom/fema320.shtm for instructions/guidelines on safe rooms.

And if the bathroom is at least 4x the total Vas of the drivers and well sealed from the rest of the shelter, it should be fine, but >10x is the optimum.

Welcome to tornado alley! And don't worry too much- I've been here 36 years and have only seen maybe 8-10 off in the distance

Mike

[twisterz]

Shelter Size
The amount of floor area per person that your shelter must provide
depends partly on the type of windstorm the shelter is intended to protect you
from. Tornadoes are not long-lasting storms, so if you are relying on your
shelter only for tornado protection, you will not need to stay in the shelter for a
long time. As a result, comfort is not of great concern, and a shelter that
provides about 5 square feet of floor area per person will be big enough.

When the shelter is intended to provide protection from storms such as
hurricanes, which can last up to 12 hours, the comfort of the occupants
should be considered. For this type of shelter, the recommended amount of
floor area per person is about 10 square feet. Necessities, such as water and
toilet facilities, should be provided. The shelter designs in this booklet are
based on a maximum floor area of 64 square feet and a maximum wall length
of 8 feet. A shelter of that size used for hurricane protection can
accommodate up to six people in reasonable comfort. If you plan to build a
shelter with any wall longer than 8 feet, consult a licensed professional
engineer or architect.

This is right out of the Fema link above. Page 14 on this link,

www.fema.gov/pdf/library/ism2.pdf

[srimes]

Thanks y'all. I've read the FEMA booklet, but plan to have a custom design that's big enough to use as a small HT, and include a 3/4 bath. Yeah, it'll be big for a tornado safe room, but it'll make the house bigger and more usable. 8x8 just isn't going to cut it.

The stiff concrete walls, floor, and ceiling should hold the sound pressure in well! I don't expect the room to vibrate, just everything in it. I'm thinking 4 mj-18s would be more than enough, and they're a great deal.

I'm thinking 10 x 15 could work for 5, with a loveseat in front of a couch, and 12 x 15 could work for 6 with 2 couches. The rear couch won't be as good a seat, but it'd be better than in most homes. I'll have to talk with the builders to see what we can afford.

[chrisbee]

I suggest you re-read the advice on safe rooms.
Have you studied room gain?
If the tornadoes don't get you then the bass certainly will.
Do you get many hurricanes in Tulsa?
Do you get power outages during either hurricanes or tornadoes?
HTs don't work without electrical power. Bummer.
Do you live within reasonable distance of your work so you can return to your HT shelter under everyday circumstances?
Are you self employed so that you can take days from work without anyone noticing?
Do you work from home so that the shelter is readily accessible at the first warning?
Can you afford an architect designed shelter?
Can you afford a shelter which includes gaping holes in the structure?
How will you know when it is critical to seal the shutters on your IB from within a small concrete box as tornadoes approach?
Have you actually tried spending hours in a small concrete box?
Was entertainment laid on?
What are typical ambient temperatures during the tornado season?
Will your wife's natural fear of tornadoes be easily dismissed by watching a film?
As you step out into a totally wrecked locality will your neighbours want to talk about the film you have just watched?
My workshop is much larger than your proposed HT.
I might wear radio headphones while working with noisy tools or machines out there.
Install an AV system? No thanks.

[srimes]

Chris: I'm not sure I understand what you're trying to say.

Have you studied room gain?
If the tornadoes don't get you then the bass certainly will.

No I haven't studied it, but have read some background info on it. So?

Do you get many hurricanes in Tulsa?

no, none.

Do you get power outages during either hurricanes or tornadoes?
HTs don't work without electrical power. Bummer.

Sometimes. But there will be times we'll go into the safe room without actually getting hit. A tornado doesn't hit the whole area, unlike a hurricane. Also, I am considering battery backup, but that would be down the road.

Do you live within reasonable distance of your work so you can return to your HT shelter under everyday circumstances?
Are you self employed so that you can take days from work without anyone noticing?
Do you work from home so that the shelter is readily accessible at the first warning?

Um, no. So?

Can you afford an architect designed shelter?
Can you afford a shelter which includes gaping holes in the structure?

We'll have to see. We're just getting started.

How will you know when it is critical to seal the shutters on your IB from within a small concrete box as tornadoes approach?
Have you actually tried spending hours in a small concrete box?

The idea is to make it into a real room, not just a small concrete box. And it will be finished, with no bare concrete visible.

Was entertainment laid on?

What?

What are typical ambient temperatures during the tornado season?

Um, 60-90*F, I'd guess.

Will your wife's natural fear of tornadoes be easily dismissed by watching a film?

No, but it'll help to be in a safe place.

As you step out into a totally wrecked locality will your neighbours want to talk about the film you have just watched?

I would guess not. At least not a first, anyway...
So?

My workshop is much larger than your proposed HT.

Mine too. Your point?

I might wear radio headphones while working with noisy tools or machines out there.
Install an AV system? No thanks.

Why would I want an AV system going while working in the shop?
Maybe that is a good idea. I'll have to look into putting a sound system and one of the auto LCD screens on my lawn tractor, so I can watch movies while mowing the grass. It already has a cup holder for my beer, so I'll just need a spot to hold the popcorn bucket.

[twisterz]

I think where this is going is build a small safe room and a large comfortable Home theater. You will enjoy the theater more times during a year than you will experience tornado warnings. All that is left is have your "New for Old" insurance policy paid so when the tornado leaves you with nothing but a safe room you get a brand new theater. Also specify that the insurance covers software, most of us have more money tied up in DVD, CD, Laserdisc, VHS, Cassette and don't forget 8-Track then in the hardware and most insurance policies don't cover any of the software.

[txsmoke]

srimes said:

What are typical ambient temperatures during the tornado season?

Um, 60-90*F, I'd guess.

Hate to be a bummer, especially since I don't know where you are moving from, but don't count on seeing 60° during tornado season down here (although this summer has been extremely unusual, but the weatherman says out 100°+ days are coming soon!) When that happens, we are lucky to get out of the upper 80s/low 90s at night.

Also, I think most people seem to feel that going with a small closet dedicated for a tornado shelter is a better use of funds. Then you can use the money you save to build a larger, better designed HT. I think I would lean that way, too. But the other may be an easier plan to get past the wife Build the 'tornado shelter' and then just happen to realize what a great space it would be for HT.

One problem I see is ventilation. 6 people and a bunch of gear can generate a lot of heat (more than you might imagine), and every opening is a potential problem shelter-wise. How are these things HVAC'ed I wonder?

Mike (just outside Dallas)

[srimes]

Also, I think most people seem to feel that going with a small closet dedicated for a tornado shelter is a better use of funds. Then you can use the money you save to build a larger, better designed HT. I think I would lean that way, too. But the other may be an easier plan to get past the wife Build the 'tornado shelter' and then just happen to realize what a great space it would be for HT.

One problem I see is ventilation. 6 people and a bunch of gear can generate a lot of heat (more than you might imagine), and every opening is a potential problem shelter-wise. How are these things HVAC'ed I wonder?

Mike (just outside Dallas)

The project does need approval from the wife, as it's basically for her. I'm just trying to sneak something in for me while we're at it.

I don't know exactly how these are ventilated. I know they have air vents and are often connected to the house HVAC, but don't know the details.

This may be a dumb idea, but if I did want to make the system run on batteries so that it works in case of a power outage, what about using car amplifiers? That would save the losses of running through an inverter. How do auto amplifiers compare cost and quality to home amplifiers? I would think they'd be cheaper.
It would use more energy when the power is on, and 120v power would be converted to charge the batteries, but when the power goes out it would be more efficient.