IB in large living room?

[mattcc22]

My living room unfortunately doubles as my home theater. It has a 21ft high ceiling and is very open to the rest of the house. The living room alone is around 6000 cu ft without adding in the kitchen, foyer etc...

First question is if the subs were installed in the ceiling on the front wall, how would it affect the sound since the subs would be roughly 21 feet from the listening position?Has anyone attempted this type of install?

Second question is if the sound would be ok, how would only 4 IB18's work in a room this large? I currently have one DIY Dayton reference 15" ported sub that will get over 100db but will not pressurized the room so it doesn't really have that kick in the chest feel.

I have been thinking of strapping my sub to the extension ladder and hoisting it up there to get some measurements and see how it sounds but that is gonna be a big ordeal

Thanks for the help

[ThomasW]

web.archive.org/web/20090103040741/http://www.geocities.com/pnwright3/Gemini_subs.html

Give the above URL time to load it's from the web archive

Bottom left pic is the IB, bottom right pic is the opening from the listening position.

Probably as big as your room if not larger.

You'd probably want more than 4 18"s

Put your existing sub in the listening position and do measurements at the proposed place you think the IB opening would go

[mattcc22]

I wish there was a little more detail on that install, but looks pretty good. I'm trying to grasp the concept of pressurizing a room vs SPL. What exactly is pressurizing a room or am I just confusing the concept with higher SPL?