Line array manifold issue

[JasonV]

I'm about to start building the manifold / box for my IB line array. It will be sitting behind my screen wall attached to the floor at the front of the room. I have attached an image that may help. There isn't much room behind the 4 x 15" drivers. Will this effect the performance of the IB sub?

[ThomasW]

It's pretty shallow, do you have access to any compressed damping material like OC 703/705 or Roxul? If so line the back wall with a layer of it.

[JasonV]

I'm sure i could manage to line it but how much performance loss with i get?

[ThomasW]

Lining it will improve performance.