House shopping. Concrete basement walls/drop ceiling - AVS Forum
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post #1 of 11 Old 01-08-2013, 08:20 PM - Thread Starter
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I sold my house 2 months ago. Been shopping hard ever since. My old house had no basement, and a garage my truck couldn't even fit into.

Those were basically the two things I told my realtor. Basement, Big garage, and newer type house. I'm a tinkerer, and the basement, well I've just always dreamed of this kick ass theater/arcade games/pool table/wet bar basement.

Anyways, found a real contender tonight as far as everything goes, except the basement has what appears to be poured concrete walls. And not like its just the perimeter of the basement and it needs framed, different rooms have poured concrete walls. Interior, exterior, you name it. It also has a drop ceiling. Man do I hate drop ceilings.

Anyway to remedy any of this? It is carpeted, I was yelling...couldn't really hear an echo. I just know once I crank up the volume, the sound has to be terrible...
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post #2 of 11 Old 01-09-2013, 11:54 AM
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Carpet and suspended ceiling tiles absorb well over the vocal frequency range. Your primary issues will be in bass modes. Find a room mode calculator (Harman has a nice one) to find how your room dimensions map into room modes.
http://www.harman.com/EN-US/OurCompany/Innovation/Pages/Calculators.aspx?CategoryID=Calculators

You can't avoid modes, but you can space them evenly and avoid co-incident modes, as occurs if, for example, room length = 2x width. Room dimensions are in your control to the extent that you plan to build internal walls, or perhaps need space for acoustic devices, a false screen wall, room dividers, etc.

You can manage modes with acoustic treatment, but most broadband absorbers have very little bass absorption, consistent with your observations. I recommend reading Chpt 12 here, paying attention to a) characteristics of what you've got (drop ceiliing, carpet) as well as b) treatments effective below 100Hz.
http://andrealbino.wikispaces.com/file/view/Master+Handbook+of+Acoustics+-+5th+Edition+-+F.+Alton+Everest,+Ken+C.+Pohlmann.pdf

Finally, it's very helpful to have acoustic measurements available. High-Q bass traps need a target frequency, and lower Q devices still benefit from being centered in their frequency response. Ears and test disc/frequency generator will do for first-order problems. From there, it's all in how sensitive you are to the residual issues. Here's a link to a freeeware measurement program; mic/mixer/cable is about $100.
http://www.hometheatershack.com/roomeq/

And as always...

HAve fun,
Frank
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post #3 of 11 Old 01-09-2013, 02:34 PM - Thread Starter
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Wow thanks a ton for that. Thats a bunch of good links there! My biggest concern is not to have to build walls. (well, many walls) The basement is only about 14x35. I wouldn't want to have to shrink it down too much further than that 14', I feel like its already too skinny especially when talking about playing pool behind the couches. I take it you are saying to definately frame in the concrete? How would it sound not doing that? Anyone have concrete walls?
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post #4 of 11 Old 01-11-2013, 03:30 PM
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Dimensions! 14x35(x8?) isnt' bad as long as you don't divide the 35' space at 14' or 28'. I don't see a reason to divide across 14', I just hope the ceiling height isn't 7'... we're trying to avoid dimensions that are integer multiples of one another.

How you build is up to you. Most folks cover the concrete to get a finished look, but concrete has some acoustic advantages. Can't find the reference now, of course...

Got to run,
Have fun,
Frank
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post #5 of 11 Old 01-12-2013, 09:24 PM - Thread Starter
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Well it doesn't appear like the deal is gonna work out. Ceiling was 8' to the drop ceiling 9' without. I did try to get it to echo by screaming and clapping in the basement (realtor thinks i'm nuts...ohwell) and couldn't get it to happen. I just felt like with concrete walls (and they were painted, didn't look terrible) but I figured they would be very harsh sounding. I may be wrong on that, was just looking for others inputs.
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post #6 of 11 Old 01-13-2013, 02:07 AM
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Sad to hear; I'd love a shot at 9' ceilings....

But it's still true that "carpet and suspended ceiling tiles absorb well over the vocal frequency range..." No surprise you didn't get an echo.

HAve fun,
Frank
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post #7 of 11 Old 01-13-2013, 06:50 AM
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Quote:
Originally Posted by derekhonda View Post

I sold my house 2 months ago. Been shopping hard ever since. My old house had no basement, and a garage my truck couldn't even fit into.

Those were basically the two things I told my realtor. Basement, Big garage, and newer type house. I'm a tinkerer, and the basement, well I've just always dreamed of this kick ass theater/arcade games/pool table/wet bar basement.

Anyways, found a real contender tonight as far as everything goes, except the basement has what appears to be poured concrete walls. And not like its just the perimeter of the basement and it needs framed, different rooms have poured concrete walls. Interior, exterior, you name it. It also has a drop ceiling. Man do I hate drop ceilings.

Anyway to remedy any of this? It is carpeted, I was yelling...couldn't really hear an echo. I just know once I crank up the volume, the sound has to be terrible...

Yelling and listening to music are quite obviously two different things. Music covers a far wider frequency range than yelling!

Carpeting is among the worst sound absorbing materials I can think of. It is a narrow-band absorber, almost completely zero in the bass and not better through the lower midrange.

Face it. Setting up a good sounding media room will take a lot of planning and work. What you see now will be completely overlaid by the time you are done.

What would I do?

(1) Set up an dedicated entertainment space that occupies only part of the basement.

(2) Partition off an outer sanctum with food and drink service, space for standing and talking and sitting and talking. Easy access from the stairs. People walk down the stairs and the hospitality suite is laid out before them.

(3) Partition off an inner sanctum for the media room that is almost completely isolated from everything else as much as possible. The room that is above it must be a space that is not going to be used at the same time.

(4) At this point if I were building a media room I would be OK with a hard floor - even concrete covered with a decorative epoxy finish. I would concentrate on the shape of the room, and the deployment of both absorptive and diffusive elements on the ceiling and the walls.
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post #8 of 11 Old 01-14-2013, 03:46 AM - Thread Starter
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I realize (or...atleast think I understand!) what I would need to do if I was wanting a 'dedicated' theater room. As much as I would love just a movie watching room, what I really want is more of a hang out room. I want a big tv (actually I want a big projection screen tv, and then two other tv's on each side for like march madness and things like that) but I don't want it dedicated. I want the room big enough to have a pool table, wet bar, a couple arcade games, my drum set, etc. I understand this becomes an acoustic nightmare, but I'm ok with having a little tradeoff on sound quality for the set up I really want. I was just nervous about the concrete, but now that that isn't panning out I'll keep looking.

Ideally, I'm going to build here in a 2 years or so. I've flipped my last couple of houses and while I enjoy the money...getting really tired of moving. Time to build something I actually want!

I have mocked up a little sketch on excel if youre still having trouble understanding. Dark Blue is tv, light blue couches, green pool table, yellow wet bar area. Speakers would be in the front, and surrounds would be where the couch is. If I did a 7 speaker system, rears would be way back at the bar area. (almost 45 feet from tv...)
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post #9 of 11 Old 01-14-2013, 05:28 AM
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Quote:
Originally Posted by derekhonda View Post

I realize (or...atleast think I understand!) what I would need to do if I was wanting a 'dedicated' theater room. As much as I would love just a movie watching room, what I really want is more of a hang out room.

IME the ideal "hang out room" is what I described. I reached those conclusions because of how I've seen crowd dynamics work out at 100s of social occasions over the decades. Some things never seem to change!
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post #10 of 11 Old 01-16-2013, 11:32 AM
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I think the question is one of degree - to what degree do you want dedicated spaces vs. multiuse spaces? There are advantages both ways; Arny's media room would be a heck of an HT, but what if you want to play pool while watching a basketball game, or perhaps at halftime? One can always use a "zone 2" scheme for sound outside a dedicated HT, perhaps with a second video display as well? A doorway at the HT would split the sound field, surround inside, stereo outside.

The simplest metric is usage: build a space you'll want to use often, based on the kinds of things you want to do. Nothing wrong with a bar-style appraoch - multiple video channels displayed, generally good sound but no "front stage" per se - just as a dedicated HT may be perfect for folks who love movies.

It's up to you what sort of space, and you have some time.. let's hope more folks have ideas...

Have fun,
Frank
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post #11 of 11 Old 01-21-2013, 04:01 PM - Thread Starter
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I appreciate your input Frank. I think that's the decision to be made, and I lean towards a multiuse space. I also gave some thought to what arnyk said and I guess I can see his point in the better theater. My end all conclusion is that once the basement is done and finished (and a house is bought, remember I'm still shoppin!) I can always alter it after the fact. Like in the crude picture I posted, if I slid the couch up a foot or two there would be room to build a wall right where the stairs break. I could throw that up in an afternoon, and am kind of wondering what a set of 3' or even 4' french doors might look light. if you could find a set of 4'x8' doors, you could just about open up the whole entrance to the theater! anyone ever done something like that?
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