I was concerned about the motors in the same manifold hitting so disregard that.
Originally Posted by diy speaker guy
LTD's most recent drawing? No, I simulated that  hasn't been simulated yet [/ edit], it still retains the big resonance problem.
I still haven't entered your actual driver specs into the sim, I've been doing everything with the same size box (whether it be U, H or W baffle) with the dimensions you provided in post 1 for the purpose of making all my sims directly comparable. Same size enclosure, same shape (overall), same power level, same drivers. The only difference is in the baffle wall itself, U, H, W shape.
I haven't done any tweaking to the sims to get the best possible response for a few reasons.
1. I haven't entered your driver t/s yet.
2. I don't know what you are going to do with the closet. Leave it? Tear it out?
3. I don't know your max dimensions and what you are willing or able to do to the house to make this happen.
You say you can't mod the rear wall of the closet at all - does it already have a hole in it?
What the max size of the "enclosure" that you can deal with? I'm going to need exact dimensions. A lot of this will depend on how big the existing hole in the wall is (if there is one), how many drivers you want per "enclosure", stuff like that.
I can get you a nice response but again, it would be better if you could measure you room gain curve FIRST so I can incorporate that into the sim. If you need help with that I can help you. And I need to know what kind of eq you have if any. Full dsp is always nice, and may or may not be required depending on what the room does to the response. As Vince said, it's not much use designing for a perfectly flat response if the room is going to shred it.
Another thing that hasn't been mentioned is that you can use a resonance peak at the top of the passband to very good advantage as Ricci has done with his MAUL and SKHorn designs. In that case you deliberately design a big fat peak into the response at/near the top of the passband and eq it down to flat. That give you less power needed in the eq'ed frequencies which is beneficial for a number of reasons.
How fancy do you want to get? Can you measure the room gain curve? Do you want extra sensitivity at the top of the passband so you can eq it down and make life easier on your drivers and amps? Are you absolutely sure you never will want to use the sub for both rooms on both sides of the wall? If not, why not? That's one of the biggest advantages to IB. Lots of questions before I start even thinking about doing final sims for you.
Room gain:150-50 +-3db 50-40hz -2db 30hz rising to 25hz hits +6db drops-2db at 20hz fairly flat to 10hz with slow rise after. I did this as close to Ricci's process as I could.
I only currently have 2 drivers with those specs I may change unless you think we can incorporate them with 2 from another maker. Im using a mini dsp and a ep4000 for the manifold the IB is currently in. Ill caught out any sheetrock needed for the mouth of the manifold, also the room is 3 block walls with sheetrock, the only framed is the closet wall.
The room opposite the theater does have a staircase leading out of it and is open to another area. If designing for both sides complicates it, theater takes precedent.
Ported or sealed boxes each box can be 55"x32"x36" max
The IB as LTD sketchup could 120"L x 42"H x 24"D, doesnt have to be like that, but that will fill most of the closet.
Those sizes work and can leave the closet. After doing the room gain measurements I realized my room is more the issue and not necessarily the closet alone. I can remove the sheetrock if needed, it will never be seen and cover with fabric.