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Discussion Starter · #1 ·
This has been an epic project that I don’t think I’ve brought up here at the shack. It commenced conceptually back in early 2011 (procrastination at its best). I finally got around to actually building it this month. A lot of other work has been going on at my house, including some basement leak repairs that require ripping out some drywall and framing studs. Once I started doing that, it was game-on for the IB. See photos and description. I am still building even though I started more than a month ago.Some of the key ingredients:

2 – 20’ 1.785”x9 LVL Beams
4 - sheets of 1.125” 5’x9’ MDF at 205 lbs each
8 – 6’ concrete lintels (162 lbs each)
11 sheets of 5/8” fiberglass reinforced heavy weight 54”x12’ sheet-rock (has to be close to 200 lbs each) (double layer on the front wall with Green Glue, single sheeting the rear wall)
6 tubes of green glue used for the outer layer of 5/8 drywall on the front wall
18 – 2x12s
8 – Acoustic Elegance IB 15 drivers (received over a year ago)
Lots of Titebond 3 and premium construction adhesive. Everything is glued and screwed.

There are six dedicated 10g armored circuits for the A/V gear, and chases to run the cables throughout the room and in between the rooms and 2-ch closet.
 

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Wow. That is going to be quite the impressive and imposing view of all those drivers! Not only that, I'm sure you are going to have a lot of fun with a lot of bass! This will be a fun build to follow! :T
 

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That should literally rock your world. May even register as seismic activity.
 

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THAT, my friends, is how you build it SOLID. Will you be treating the walls with the OSB, green glue, rock layers too?
 

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Discussion Starter · #6 · (Edited)
Thanks guys. The wall is already 12" thick. I set the baffles so that when I put grills over the baffle, the grills will be flush with the drywall.

There's no OSB in there. The 5/8 drywall is pretty robust and heavier than OSB. I didn't think the difference in rigidity would be significant where it is installed. The baffle structure itself is very stiff!

I will be putting up an Elite Acousticpro 4k acoustically transparent screen, so with everything behind the screen being black, it should be quite invisible.

The drivers will be completely concealed in the wall too. So the rear room won't have back of the drivers sticking out of the wall. It will become a music room for my kids. I am wondering if I could plug my son's bass into the IB. That's a low priority though. Obviously the music room and the HT won't be used at the same time.
 

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Discussion Starter · #8 · (Edited)
Owen - The lintels are vertical, both bolted and glued to the 2x12s. The 2x12s along the baffle structure are also fastened with screws and glue to the baffle structure. The 2x12s were really there for nailers for the drywall, but they ended up adding quite a bit to the structure. The lintels do not rest on the floor. The entire weight is in the vertical part...which ends up on the floor of course, but the thought was to move it, the whole wall would need to move.

The lintel idea came from Chrisbee over at the cult forum. While I think he felt they would be best for structural rigidity being used for the main structure, I used them for both rigidity and mass...mostly mass, as I don't think they do much for me structurally. His IB is in a concrete wall. That's a best case scenario for a vertical array but I didn't have that option.

At $19/piece, the lintels are cheap mass and very strong since they are reinforced concrete. When fitting them, there was a noticeable difference just knocking on the wood parts when they were bolted only vs. bolted and glued. Bolted and glued are noticeably more solid (damped). Then there are four lintels just bolted and glued to some other 2x12 studs near the baffles. They do add stiffness, and of course mass and dampening, which should help keep the wall stable. I guess the knuckle wrap test is mostly a dampening test...thats where I notice them the most at this point.

The wall itself is now stupidly solid with the drywall installed. The drywall finisher is doing final sanding today. Once he's done, and I pull the plastic down, I can get some pics. I'm really glad I left the mudding to a pro. He's done a much better job than I could have ever done.
 

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Owen - The lintels are vertical...

The lintel idea came from Chrisbee over at the cult forum. While I think he felt they would be best for structural rigidity being used for the main structure, I used them for both rigidity and mass...mostly mass, as I don't think they do much for me structurally. His IB is in a concrete wall. That's a best case scenario for a vertical array but I didn't have that option.

At $19/piece, the lintels are cheap mass and very strong since they are reinforced concrete. When fitting them, there was a noticeable difference just knocking on the wood parts when they were bolted only vs. bolted and glued. Bolted and glued are noticeably more solid (damped). Then there are four lintels just bolted and glued to some other 2x12 studs near the baffles. They do add stiffness, and of course mass and dampening, which should help keep the wall stable. .
Congratulations on your project! It's good to see an idealised construction being put into practice with such obvious commitment.
Your sensible design principles should offer a level of rigidity (with mass) few others have achieved by the usual methods.

The lintels add the belt to the braces of your very deep beam sections. Far better than simply applying more layers to the surface of a normal stud wall. Which is the usual quick (and dirty) fix.
The danger with just adding slightly thicker wall surfaces is getting a high mass but still very flexible baffle moving, due to reaction forces and then being completely unable to damp it.
You can't fix a flexible footbridge, or dance floor, just by doubling up on the floor boarding.

I wish I could lay claim to the ideal concrete baffle wall but my present home is far too flimsy to allow anything but an opposed driver manifold.
Should I ever have access to a more solid home I shall closely follow your own methods.
I hope others will be paying careful attention to your example of how to build a baffle wall properly. :T
 

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Discussion Starter · #12 ·
Thanks Chrisbee! - I guess I was wrong - I looked at a lot of different examples as well as reading through my own thread at the Cult where you, Thomas, FOH and others were a wealth of information and suggestions. I thought yours was in a concrete wall, which I figured if I won the lottery and built my personal man-cave, I'd include a concrete IB into my listening room.

This is definitely a lot of work. I can't wait to get it all up and running. I'll be using a Xilica XP-4080 for the signal processing which are used by my Legacy Audio main speakers. This should provide seamless integration. I have two QSC RMX-2450 amps that I got used more than a year ago. I am thinking I'll only need one, but I'm holding onto both just in case.
 
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