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Sub in the attic?

post #1 of 17
12/18/07 at 5:22pm
Thread Starter 
Is there a significant downside of a sub in the attic?

I was thinking about an NHT1259 (well, now MAD1259) project and then got to thinking about how car guys always put subs in the trunk and such. So... that put the possibility of attic mounting subs with no cutout in my head.

So really I have 2 options for how to build the sub:

a) build to be placed in the attic with no cutout and have freedom to place it almost anywhere on the x/y plane but 8 feet above the floor in the z plane and with a sheet of whatever "typical ceiling material" is between the sub and the listener.

b) put sub under one of the mains and have no issue with filtering through the ceiling, but have very little placement flexibility.

My guess is that the placement options available through ceiling mounting are going to potentially offer better sound than putting it in the room but be chained to one of 2 very specific locations.

While I can build and test both ways, I kinda would prefer to avoid that... the cabinet designs are going to be quite different for the different applications considering the aesthetic concerns if it's inside the room vs. attic placement where the only real design constraint is going to be fitting it through the access hole into the attic (and figuring out how to lift such a behemoth up there and how best to move it around while walking on rafters since the living room is a good 20 feet from the attic access location.)
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post #2 of 17
12/18/07 at 7:47pm
You want to implement an infinite baffle setup. This will allow you to construct a simple manifold type setup. You can see some examples of that over at "The Cult".
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post #3 of 17
12/18/07 at 8:25pm
Quote:
Originally Posted by Concillian View Post

then got to thinking about how car guys always put subs in the trunk and such. So... that put the possibility of attic mounting subs with no cutout in my head.

Technically there is a cutout. Most trunks have nothing but some springs and a little fabric on the back seat separating the trunk from the cabin. Those are great for trunk mounted subs. Cars like some BMW's and Lexi (plural of Lexus) have a gas tank or metal wall separating the trunk from the cabin. Those suck when you mount a sub in the trunk. Those require IB subs mounted in the rear deck. Just like jpmst3 suggested.

-Robert
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post #4 of 17
12/18/07 at 8:46pm
Quote:


that put the possibility of attic mounting subs with no cutout in my head

Fortunately you won't need a cutout in your head......

But you'll certainly need one from the attic into the listening room, otherwise it's a waste of time, money, and materials.
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post #5 of 17
12/18/07 at 9:28pm
Quote:
Originally Posted by Concillian View Post

a) build to be placed in the attic with no cutout and have freedom to place it almost anywhere on the x/y plane but 8 feet above the floor in the z plane and with a sheet of whatever "typical ceiling material" is between the sub and the listener.

You're able to move the sub anywhere in your attic, for best accoustics in your attic. You wont get the results you're anticipating. To test it, set your sub against a wall, and listen to it in that adjacent room. Now go listen to it in the room it's in. There should be a huge difference, anywhere from 10 to even 25+db. Certain wall designs can even kill up to 64db's (just wish I could find that link again)

You'd be better off building a few small enclosures for 8's or even 10's and stealthily place them in your room. Maybe some small under-couch subs?
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post #6 of 17
12/18/07 at 10:31pm
I actually did some testing and currently have a sub in my attic. It's for my bedroom HT. All speakers are Klipsch inwalls and gear(except DVD) is in the attic (WAF). The system was really lacking in bass. I lugged an old 12" klipsch sub up to the attic and started playing around. I tried using it several ways. Thru drywall was aweful. Barely any sound in the room but loads in the attic when I opened the access door. Also, very loud bass in bathroom, thanks to vented light, my wife discovered this feature. I ended up cutting a hole in the ceiling and installing a grill left over from the inwall speakers (5.1 set up...had to buy speakers in pairs). The sub sits directly over the grille. I think the system sounds very good for what it is. I do however, also think that the sub would sound better in the room.
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post #7 of 17
12/18/07 at 11:32pm
Thread Starter 
Quote:
Originally Posted by Looneybomber View Post

You'd be better off building a few small enclosures for 8's or even 10's and stealthily place them in your room. Maybe some small under-couch subs?

Your couches must resemble park benches... mine certianly do not. No "sub" I can fit under one of my couches is going to put out any useful frequencies.

It gets done right or I wait a while and make much larger mains. I re-measured and there's not really enough room under the mains I have now unless they move substantially higher.

New mains could be smaller if there is less need for bass, and this would allow for them to move higher because the tweeter would not be as high as they are now. But one project at a time, and it's been 10 years since I last built a speaker, I'll stick to the easy project first (subs are simple, driver, sub-amp, sturdy cabinet, find best location with short FR sweep, adjust Eq if you have one, done... speakers involve testing baffles and crossovers, by doing lots of much larger frequency sweeps. Those two steps alone are more than an entire subwoofer project).

If there needs to be a hole, then I have to consult the "interior design engineer" (a.k.a. wife), and when I need to do that I end up using favors that can be used elsewhere... so you can understand the reluctance. But that's why I asked.

I imagine a hole with a fake furnace return is going to be the preferred option when compared with a sub cabinet somewhere in the room, however I'm guessing the truly preferable option that the interior design engineer will choose will be "yeah, we don't really need that do we?"
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post #8 of 17
12/20/07 at 5:10am
Quote:
Originally Posted by Concillian View Post

If there needs to be a hole, then I have to consult the "interior design engineer"...however I'm guessing the truly preferable option that the interior design engineer will choose will be "yeah, we don't really need that do we?"

I thought I had it bad, but you sir have it much worse!

An infinite baffle has to be the best WAF design there is. It's also fairly easy since there's no enclosure to build. If you can't get the green light on that, I don't know what to tell you.

Will your wife be kosher with large mains so long as they're asthetically pleasing? You could go the route with a powered sub in each tower. It wont net you flexible placement options, but it's better than having zero placement options at all!
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post #9 of 17
3/1/09 at 1:02pm
I was considering subs in my attic. I see only references to just putting them there, not actually building them in with proper sound pathways, grill cloths etc. I don't like down-fire, so I was considering setting them to fire into 45 degree reflectors in the last rafter cavity. There is no place to be stealthy for 4 60L boxes in my room. I live in it.
I prefer sealed subs, so a band-pass port design would not make me happy.
One down-side is amp location. Long leads whatever I do.
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post #10 of 17
3/1/09 at 1:23pm
Quote:
Originally Posted by tvrgeek View Post

I was considering subs in my attic. I see only references to just putting them there, not actually building them in with proper sound pathways, grill cloths etc. I don't like down-fire, so I was considering setting them to fire into 45 degree reflectors in the last rafter cavity.

Make life easy put a manifold design IB sub in the attic..






Lots more pictures here
http://home.comcast.net/~infinitelyb...B-Gallery.html
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post #11 of 17
3/2/09 at 6:34am
Manifold design looks to be the ticket. Wonder what kind of loading the manifold creates with two facing drivers into a 24 or so cube?

I have no experience with IB or suitable drivers. I have always preferred low Q sealed boxes. Peerless XLS my current lowest distortion favorite. Any driver recommendations?
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post #12 of 17
3/2/09 at 6:38am
Quote:


Manifold design looks to be the ticket. Wonder what kind of loading the manifold creates with two facing drivers into a 24 or so cube?

I have no experience with IB or suitable drivers. I have always preferred low Q sealed boxes. Peerless XLS my current lowest distortion favorite. Any driver recommendations?

It looks like AE's IB15s are a very good choice now or IB18s from Ficaraudio.com
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post #13 of 17
3/2/09 at 6:42am
Quote:


I imagine a hole with a fake furnace return is going to be the preferred option when compared with a sub cabinet somewhere in the room, however I'm guessing the truly preferable option that the interior design engineer will choose will be "yeah, we don't really need that do we?"


My wife has zero issues with my IB array in the ceiling of the family room....12 feet high, no one ever notices until its on



Here is the baffle board installed in attic before re-inforcments,before drivers, before the holes were cut.

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post #14 of 17
3/2/09 at 6:54am
Quote:
Originally Posted by tvrgeek View Post

Manifold design looks to be the ticket. Wonder what kind of loading the manifold creates with two facing drivers into a 24 or so cube?

I have no experience with IB or suitable drivers. I have always preferred low Q sealed boxes. Peerless XLS my current lowest distortion favorite. Any driver recommendations?

Read the IB FAQ link in my signature.

FWIW, with an IB the Qts of the driver is the Qtc of the system

If you sign up for the Cult forum you can see literally hundreds of threads about IB sub installations. And info about the drivers we recommend for this application.
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post #15 of 17
3/2/09 at 7:00am
Just back from viewing the "cult" pages. Think I'll give it a try. Just to be different, I'' do a manifold so I can compare my large sealed with IB. Looking at the pictures, I am glad to see there are some seriously sick puppies out there.
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post #16 of 17
3/2/09 at 8:32am
Dont seem like you would get the full BASS output with them in the ceiling? Seems subs need to be low on the floor?
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post #17 of 17
3/2/09 at 8:37am
Quote:


Dont seem like you would get the full BASS output with them in the ceiling? Seems subs need to be low on the floor?

That would be one of those audio myths

you get full BASS output no matter where your sub is, the wavelength is huge and more then fills the room.
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