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Discussion Starter · #1 ·
Fellow Shacksters have helped me design a large vented enclosure for my LMS-Ultra drivers and I have submitted the plan to the authorities (my lovely wife). She says, "why not put those big-honkin' speakers in the ceiling?" So, why not? I plan to put them in the front two corners, so would there be a difference if they were mounted in the attic firing down through the ceiling corners?


My room:
13'x20'
45 degree vault splits the 20'
attic space is on the left for the enclosures - both boxes would be on the left corners

Demo begins the day after Christmas for the remodel of this room, so I can hoist the enclosures through the vault, secure them in place in the attic, etc. Since I have all this space in the attic for any size enclosures, maybe I should get the most out of these Ultras and build Ricci's G-Horn?

Thoughts guys?
 

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Discussion Starter · #2 ·
Ok, a friend reminded me that I should start with some measurements. I took some measurements from the place that my sub usually sits from my LP at the couch up to 80hz. Then I moved the couch and realized that we are filthy animals and need to vacuum under the couch more often, yuck. I moved the sub aimed at the wall since I get rear wall reflections from my LP, as the couch rests against the back wall. I moved the UMIK around the room in my possible places for the subs, in wall and out: top corner front left, bottom corner front left, bottom corner front right, back upper corner left, top front center.

My measurements conclude that a sub behind the ceiling joists in the attic firing down through the front left corner is tied for best response with the bottom left corner loaded sub, followed by the top front center at the peak of my vaulted ceiling is a close 2nd. The best of all other combinations I came up with are 6db or more behind the other positions.

It would be easiest to have 2 subs in the upper left corner, but I could take advantage of some smoothing if I can position them in 2 different places.

I have several positives that come out of this:
happy wife with more floor space
I can move on with the design of the living room remodel
I can build some LLTs for my pair of LMS-Ultras
I can build some Statements for either side of the TV now that the subs are off the floor
the money I spent on the CSL UMIK just paid off in a few short hours


Red line is upper left corner ceiling
Blue is behind the wall top front center
Green is current placement, floor front center
Brown is lower right front corner
 

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Sounds like a good idea. :)
My only concern would be what kind of roof you have? If it is a clay tile I might be concerned with breaking the roof tiles if you get a lot of bass (might be more of a concern with a IB setup though... Not sure just something to think of. You could always put some plywood up to seal the roof a little better though.
 

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Discussion Starter · #4 ·
It's wood shake. I have the same concern. The vibrations from the enclosure worry me most and padding the wood they sit on and building the cabs double wall will help.
 

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It's wood shake. I have the same concern. The vibrations from the enclosure worry me most and padding the wood they sit on and building the cabs double wall will help.
I wonder if you could isolate the cabinets from the roof like they do when you build a theater... Or maybe get some Sorbothane ( http://www.sorbothane.com/standard_product_guide11.php ) and make a nice thick gasket for the hole that the sub will be resting on.
 

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Discussion Starter · #8 ·
That is a good idea. My first thought was to glue it down with PL, but I would never be able to replace the driver if I need to. I need something so the ceiling doesn't rattle. In addition to the double wall sub enclosure, I could glue the Sheetrock and even double layer it as well.
 

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One more thing... Are you going to br running a ceiling mounted projector? If you do, you might want to decouple it from the ceiling too.
 

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My measurements conclude that a sub behind the ceiling joists in the attic firing down through the front left corner is tied for best response with the bottom left corner loaded sub, followed by the top front center at the peak of my vaulted ceiling is a close 2nd.
Not sure what you mean by "best" response, but looking at your measurements it seems that corner placement seems to give loudest response while centre placement gives smoothest response. Personally, I would try for smoothest response and then raise the level to suit my tastes.

To that end, any chance you could mount the in-ceiling subs above your couch for nearfield bass? This way, you hear more of the subs and less of your room.
 

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Discussion Starter · #13 ·
I would need to re-EQ for sure. My goal is smooth and loud. I hope that spreading the subs out a bit will help smooth the response naturally, and I will add a 3rd whenever I can get my hands on a used one. I thought about a near-field mid-bass module on either side of the couch, but that will be much later if at all. The 50hz dip is EQed in because that frequency is overwhelming for some reason when I'm on the couch. Most of the humps in the different positions also reflect gain added to that frequency on the DSP. There is also an 80hz XO on the 818.

I don't plan a projector in here. This is where we do most of our entertaining and hang out as a family, and I spend a lot of time reading and listening to music on my off days when the girls are gone. The HT room in our basement has the PJ. That room gets a makeover next year. I redo one room a year since we have had the house over the last 5 years. It's slowly creeping out of the 70s.
 

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Here is a thought... Are you on a sub floor? If so maybe you could put the subs in the floor which would eliminate any ceiling problems plus the weight would not be an issue. I remember years ago seeing an article where someone made their whole basement into a subwoofer.
 

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I hope that spreading the subs out a bit will help smooth the response naturally...
Try spreading them out to the quarter points of room width, as suggested by Floyd Toole:



Should cancel your room's first three width modes (28Hz, 57Hz and 85Hz) for smoother response across your entire seating area.
 

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My HT is under the floor in the basement, so subs underneath isn't an option
I'm confused now... I thought you were trying to mount the subs in the attic?
 

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These subs are for the living room setup upstairs, the dedicated HT is in the basement.
Ooh... Now I understand.

Too bad you couldn't have the HT subs in the ceiling and dual purpose them for the living room.
 

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Discussion Starter · #20 ·
Sanjay - thanks for the info. What I get from the graph is that if I keep the subs in the corners or quarters, the response is smoothest. The way I have it planned with one sub upper middle, the second sub upper left, I would have the center sub pivoting right on a null since the room is 20' long, which would cancel out sound in certain frequencies. So mulitples would be not good in this arrangement? Am I on track?
 
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