Space limited manifold

[chambers1517]

Ok here we go again. I had built a bedroom and started a theater in my basement. We had a flood in the basement and had to gut it so I am starting over. We reconfigured the basement and eliminated the bedroom. We are building a theater and a den. I have started the theater with an IB being one of the main goals. The theater area is 14'x31'. I am building a false wall 6' out which will result in a14'x25' room. The false wall is basically in the middle of the old bedroom. There is also a door in this IB space which goes into a 6'x10' closet which was in the old bedroom. I am going to install a new door at the other end of the closet which will be in a hall. Basicall if I leave the old closet door open it increases the size of my IB chamber. I hope this makes sense. Here is my problem. My front speakers will be 3 Lascalas. I like them recessed in the front wall covered with speaker fabric. I want to build boxes for the speakers to sit in so I can seal the front wall. I have a 12' wide scope screen. The screen goes from the top of the speakers almost to the ceiling. I have about 2 ft on each side of the center Lascals. If I install a manifold on each side of the center, the backside of the drivers will be fireing right into the sides of the speaker boxes. What impact would there be to build manifolds with a driver at the rear and one on top instead of faceing each other? I want to use 4 FI 18's

[ThomasW]

Dec 15, 2010 8:07:30 GMT -7 chambers1517 said:

r Lascals. If I install a manifold on each side of the center, the backside of the drivers will be fireing right into the sides of the speaker boxes. What impact would there be to build manifolds with a driver at the rear and one on top instead of faceing each other?

No mechanical cancellation of the vibrations off the drivers

[chambers1517]

Any idea what the best solution would be? How far from the floor would these need to be if I were to put the drivers top and bottom. I only have about 30" to the bottom of the screen.

[chrisbee]

IB drivers are not usually happy pointing up or down.

[ThomasW]

Dec 15, 2010 16:00:58 GMT -7 chambers1517 said:

I only have about 30" to the bottom of the screen.

Then you probably want to forget about manifolds and mount the drivers firing forward into the room. Would need to use 15"s instead of 18" if this 30" thing is a fixed dimension

[chambers1517]

Thomas' how much room is required behind the back of the drivers? I measured and it looks like I would have about 16" on each side of the manifolds.

[ThomasW]

One of the main ideas of an IB is having unlimited unrestricted space behind the drivers.

This is why I made the recommendations in my previous post,

[chambers1517]

Thanks, Without the manifolds I have about 4 feet between each speaker I think I can put 2 18's on each side of the center if I raise one up some. Like a line array but one driver higher than the other. What about this idea? I know the wall needs to be as stiff as possible.

[ThomasW]

That sounds fine

[chambers1517]

Hey Thomas how about this thought? I worry about all the issues with a line array. What if I built a heavy duty box recessed into the wall. I could then mount the drivers in the top of the box firing down. I could leave the opening in the wall. Basicall it would be a line array but the movement would be up and down. I have a concrete floor and I could bolt the box to it and not worry about flex. So what I am thinking is a manifold but with the drivers in the top so I can use the concrete floor as an anchor.

[ThomasW]

I really don't see how this is any better than a well braced front facing baffle.