Open walls...

So I'm looking at building a new house and that will involve a new HT.

My current setup is a 7.1 in a ~14x18 room. Works well, but has limited seating.

Given the new house is completely unbuilt, I'll get to do it however I want. If I go with a completely separate room, I'd probably want to go with something like a 17x30 room, allowing for some 'stadium' type seating as well as the inclusion of a bar. The HT doubles as a space where I show off images and meet with my photography clients.

However, I've got a roughly 35x45 space (or whatever) to build within and part of me is thinking the overall flow of the space (it'll be a photography viewing and shooting space) would work better if the HT wasn't a 'separate' room but instead was simply a separate area (kind of like this: http://www.gcscontractingonline.com/images/basement.jpg but on a larger scale)... In other words, it'd be a 'sunken space' within a larger space with open sides and open 'back' (just posts for support to separate the space from the larger space and to mount speakers and such)

Now -- how does this affect sound, not having walls to enclose the sound? Good, bad? Are there benefits/negatives to having the space enclosed vs open to 'non-theater' areas?
Edited by MN Photography - 7/26/12 at 12:54pm

Thanks for the responses...

Okay, my current setup was just in a retrofitted basement room with no sound changes other than some 2x4 half-walls and furring stuff put up in order to create some shelves and run wire and hang drywall for aesthetic reasons... so please be kind when I ask this basic question:

What's the point of all the sound proofing? I've been reading a ton about GG, multiple layers of drywall, various 'clips', sealing up the rooms with 'great stuff'-type spray foam sealant, etc... Is the point to make the room sound/function BETTER.... or is all that work simply intended to keep the people sleeping upstairs from hearing your theater and people in the theater from hearing the racket going on in the rest of the house?

I get the concept (But not really the specifics) of 'acoustic treatments' -- handling reflections, bass traps (this will be big for me, the bass is so 'boomy' and 'hangs out in the room for a long time' in my current setup), etc... but I haven't really seen someone explain the 'why' behind all the esoteric measurses people take at soundproofing.... ya know?

My home will be an ICF home (6" concrete sandwiched between 2" (or more) of EPS foam) including the horizontal surfaces and many of the interior walls as well... heat will be mostly done via radiant floor heating and other 'silent' options (likely a mostly passive solar home, with exceptions in some months due to the extreme climate of MN). The family, when watching a movie, is watching a movie (duh!) and thus sound leaking out into the bedrooms or what-not isn't a huge deal. (the only thing between our current system and my bedroom is one layer of drywall, one layer of OSB, and my bedroom carpet... and it's never once bothered me. 12" of concrete/EPS foam will, likely, be 'better' than that. I think? )
The master is one floor up and the rest are two floors up.

We have one kid and will potentially have another... but either way, like I said above -- if the theater is bumping, I'm probably not trying to sleep anyway.

My main concerns are being able to throw a good party utilizing the space (even if the screen isn't on... this floor of the house is effectively our 'rec room'), being able to have a great theater experience (even though we'll rarely have more than 4-6 people dedicatedly watching a movie), and using the space/screen as a 'photo viewing' area for my business (which will also be run out of this space).

Edit: I should also note that I fully expect some video gaming to go on on this thing. FWIW.
Edited by MN Photography - 7/30/12 at 8:33pm

I'm currently in the St Anthony/Columbia Hieghts area but will be building in Arden Hills (a plot of land with a demolished house) in a year or two... and I'm trying to come up with some good options.

But doesn't that miss the point? If I'm in the room, I'm not up sleeping.... so it doesn't really matter. Let's say it's 10 years from now and my kid is a teenager... I'll tell him to turn it down or turn it off, same way my parents had me keep the TV down when I was growing up.

I've been up there... yeah... it's louder than I'd want if I was trying to sleep... but like I said, there is really nothing between there right now and this future place will have 12" of concrete/foam as well as whatever ceiling and flooring we put in. Either way, from your answer (thank you, by the way... I'm sorry for the basic quesions) it sounds like soundproofing is more of a technical solution to a social problem than a technical problem that actually results in better sound... Correct me if I'm wrong?

I'm learning that now. My current 'boomy' setup is simply a rectangular room with everything mounted/setup. It wasn't 'treated' in any way for anything. I'm trying to learn from those mistakes for the upcoming build.

The 'room' is going to be a 1500-2000sq foot open floor-plan room that, from a business perspective, will be used as a client meeting room (showing them images while we talk and go over contracts -- I'm a photographer), a editing location (standard 'home office' stuff, but with more computer stuff and a shelf of camera gear), and a smaller studio area. I am a boutique photographer and don't do high volume - as such, I only really use the space with clients about 20 days a year. (though I'm in the 'office' area about 360 days a year)

It's my understanding that one of the huge benefits of ICF construction (particularly interior walls and flooring) is that sound basically doesn't come through. The stats I've seen is that the 6" walls (with 2" EPS on each side) have about 1/3 the transmisivity (is that a word) of a 2x6 fiberglass insulation-filled normal exterior wall (so clad with siding, osb, and one layer of interior sheetrock). I don't have stats for the 12+" horizontally-spanning sections, but I can't imagine it'd be MORE transmissive. Is two layers of gypsum and some glue really more acoustically-blocking than 4+" of EPS foam and 6-12" on concrete?
Would I need more than that? If people really think it'd be worth it, I'm all about doing it right the first time.... but it just seems like I'd already be at the point of diminishing returns before I even put up the visually-requried single sheet of (likely sheetrock) cladding. No? Again, I'm new, so correct me where I'm wrong... I'm just flying be the seat of my pants at this point.
Which is why I'm here before my building plans have even been created. I figure you all have done, or seen this done, so many times you know where the mistakes occur.

Are there any thoughts on potentially putting a theatre in at a 45 degree angle to the room? Pros/cons -- particularly for sound?

Just wanted to say thanks for the info re: sound proofing. Very helpful and will help direct my questioning and research going forward.

I'll certainly be back more in-depth as I get further along in my design...

What steps are needed to be taken to ensure reasonable performance (ignoring social issues like "keeping the wife and kids happy" for now and more 'performance' issues already discussed like sound-floor issues like ambient noise levels) with a room that's dedicated, but has a more 'open' plan? Something like the front 12 feet 'enclosed' with the back 12 feet 'open' to the rest of the room with colums at 12, (for mounting the sides and defining the edge of the 'enclosed' area and the back corners at 24 feet or something... Do the sides perform better mounted 'into' the columns or 'on' the columns. Are dipole speakers kind of a must-have in this type of situation (where some people will be sitting even with the sides and others will be significantly behind)? It's my understanding that rear speakers are to be closer together than 'in the corners' and shouldn't be at the top-- would it be better to mount them on the back columns or even further back (say 35 feet from the front speakers) on the actual back wall? ... or potentially IN a bar-top area spanning between the back two columns (though that puts them about 12" from the back of the heads of the people in the back row)? Is 7.1 going to be the standard for a significant period of time... or is there something 'just on the horizon' that I should plan (even if it's just conduit to areas) for? You see the main thrust of my issues?

Beyond the speaker placement -- Would I need to significantly acoustically treat walls outside the space? Would the open space surrounding the actual theater work to help tighten up the bass (leaving me from needing to make as many bass traps) by giving it more space to degrade on it's own, or would I actually be exacerbating the 'boomy' issue by having walls open to more area that would, as a general rule, be untreated (simply drywall over furring strips on 2" closed-cell-foam over concrete)?

Visually -- are there reasonable ways to deal with getting good picture quality from a projector while still having ambient lighting (low level 'party' type lighting, but certainly enough to read contracts and such) in the rest of the space... or is that just simply asking to be dissapointed with the wash-out projector look we all know and love?

Another concept that might work well with the layout is to place it all at a 45 degree angle into one of the 'corners' of the space --- any thoughts on that?