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Discussion Starter · #1 · (Edited)
Here is a photo of the cabinet I have to work with. I plan on removing the cabinet doors to accomodate two sealed 5cf subs, each housing a single IXL 18.4, front firing. Never mind the text on the photos. I have decided not to do an IB install with these subs as I don't think two 18's IB is going to provide enough output, and while I have plenty of power and seven of these IXL18.4's lying around, the closet behind the wall is only about 200cf, or 10x Vas for two of these subs.

http://i195.photobucket.com/albums/z196/zacjones99/LRlayoutsketchR.jpg

Above the subs will be a center channel, and above the center channel will be the TV. Hopefully this design with the built-in subs and center channel will not create horrible resonances within the over 10cf space behind the TV. There is full length shelf separating the subwoofer space from the center channel / tv space. Would wrapping up a bunch of owens-corning fiberglass insulation in a sheet and stuffing it behind the TV help any to reduce cabinet resonances? I have a ton of that stuff left over from a remodel of the last house we were in.

I have seen it recommended here to use a combination of 1" and 1/2" high density latex foam to line the walls of the subwoofer space within the cabinet. Should the enclosures be a tight fit into the cabinetry? Or should I allow for an inch or two between the enclosure and the walls of the cabinetry? Also, the latex foam would add about $100 to the project. Is there a cheaper way to achieve the same results?

Foot spikes would surely make it more difficult to slide these subs into the enclosure, unless it was done while sliding in the latex foam.

Any more drawbacks or considerations to this type of installation? Recommendations? Thanks. Zac.
 

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You will want to decouple the sub from the structure or the vibrating cabinet will sound terrible. I've always heard Extra Firm Latex foam is the right thing for the job. I suppose you could try styrofoam. I'd get the blue stuff if you go that route.

There are many drawbacks to this type of installation.

1. Ideal sub placement can't be achieved.

2. Box size limitations.

3. Vibration in a cabinet.

I'd suggest you put one sub where the statement goes and one under the tv.
 

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Wow, I don't think you going have much success getting subs in that cabinet to sound right and like lsiberian said getting the cabinet and everything on not to rattle would be difficult at best. It looks like a nice house is there another room you could use for a TV room? One option would be an IB in the attic with a small vient into the room. A moterized screen or a picture that hides a tv over the fireplace would be my first choice. http://www.vutec.com/Products/ArtScreen_Products/ArtScreen

With that much tile that room will have an echo, make sure you put a large area rug down.

Matt
 

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Discussion Starter · #5 · (Edited)
I'm probably going to put the center channel on heavy duty drawer slides so it can be pulled out of the cabinet for critical listening during movies and such. The TV won't be on a stand, but mounted on 2x4 framework and a flat panel mount, so vibrations will be minimized there too. The only concern then would be the stuff on the top shelving, which we could do books in so the cabinet vibrations aren't a problem unless the cabinet itself rattles or the drywall around it starts to crack. I understand this is a challenging install, but I'm determined to make it work the best I can.

The main problem as far as the subwoofers go is that this is a pretty good sized house with a very open floor plan. It's a 2-story 3200sf house with the only interior doors downstairs being to the bathroom, the laundry room, the closet, and the pantry. I have a feeling it's going to take a lot of subs to get it done. I will likely end up adding two more of these 5cf sealed subs to either side of the sofa on the back wall, and use them for bases to the surrounds, but I'd prefer to start with the stealth project and add on only if needed.

I think that if I were to do the drawer slide for the center channel, then I would also leave the doors on the sub cabinet and just open them up when it's time to party too. That would also deter people from running into the exposed center channel.

So Isiberian I think from the drawbacks you listed the one to present the most significant problem could be the cabinet vibration. I'm not too concerned about the location being perfect as it will likely blend in with the other subs if I put them on either side of the sofa. I'm also not too concerned about the box size limitations because I think I can make it work. So I guess I'll just go at it gung ho to try and minimize the cabinet vibrations. Maybe in addition to lining the sub area with latex foam I'll apply some sound deadening mat to some of the large panels in the entertainment center? Would putting OC703 or some kind of room treatment inside the voids be helpful, if not for the sub frequencies, then for full range frequencies?

And yes we are likely going to go with a projector at some point down here,but we'll still be needing daytime TV so the plasma will always be in demand. Thanks for your comments you guys.

Mdrake yes I considered an IB, but this is a two story so I can't access the attic. Behind the entertainment center is a 200cf closet though, and I did consider doing a two-sub manifold in the proposed location, but the closet only provides 10x Vas for two subs, and with the listening position almost fifteen feet away, I don't think a single pair of 18's IB will cut it for such a large open space. I also considered doing another two sub manifold in the cabinet behind the statement on the R side, but that would reduce the four subs to having about 5x Vas, and I definitely don't want to build my hall closet into a sealed enclosure, so I dropped the idea. I'm not even sure if four subs IB would have cut it. I'm thinking I'll have a better fighting chance if I go sealed. If four 18's in 5cf sealed cabinets doesn't cut it, then at least I went at it with guns blazing, and I didn't tear up the closet or the backs of the built-in cabinetry. There's no way I could get away with LLT's or Horns in here.

And yes, I've got a big fat wool rug going in first thing.

Thanks for your comments you guys. Keep the ideas coming please!
 

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I don't see anything wrong with 5 cu.ft. per sub. Yellow is what two 5 cu.ft. subs would produce with 1500 watts input power and no hi-pass filter. Orange would be 4 subs in the 200 cu.ft. closet with 3000 watts and a hi-pass filter at 14 hz. The 4 subs would have a 7 db advantage over the 2 sealed subs.

ixl.JPG
 

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Discussion Starter · #7 · (Edited)
To get those results from the closet would I have to build the closet into an enclosure? Or could I just leave it as is?

I started a cult thread on this too now.
 

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Discussion Starter · #9 ·
The FAQ over at the cult states that with 4x Vas, one would need to build the backwave area like a standard enclosure. 5x Vas is OK though?
 

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Just fill the closet up with pillow stuffing that will fix it. :dumbcrazy:

Matt
 

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Discussion Starter · #12 ·
Hehe. That would be an even tougher sell than the floorstanding speaker in the hallway! :wave:

Another problem with this IB location is that it's 200cf empty. I know we're going to keep at least a vacuum, coats and shoes in there. We're going to lose quite a bit of storage under the stairs if we try and limit the amount of stuff we put under there to save space for the back wave.

I should have considered this before. I think the IB is out unless I can put a window to the garage in the closet. That's getting pretty far out there though... :ponder:
 

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Discussion Starter · #13 ·
So I was told by a respected member of the forums that I shouldn't build the IXL 18.4 subs into 5cf enclosures unless I want poor sound quality. The rationale being a high Vas driver should not be in this small an enclosure.

Mach5audio, while recommending 4.59cf as its sealed box size, at the same time states "Optimized for Large Enclosures and Infinite Baffle Configurations". 5cf is not really a large enclosure for an 18. Is it possible that 5cf is recommended for car audio and a larger box would be recommended for home use?
 
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