No, not really. With that much volume and a suitable driver the roll off will be natural. Sealed designs come into their own when given enough volume. They have the advantage of simple build, zero chance of port resonance above the fundamental and no need for a high-pass/rumble filter to protect the driver from unloading. All wins in my book if you have the space (which you do).
Every sub regardless of design has an EQ anyways. Sealed, ported, band-pass, etc...
The nice thing about a managed EQ is you can have different settings. Maybe a ruler flat 20-80Hz, maybe a house curve with +3db from 35-55Hz etc. Takes me about 5 seconds to recall a ruler flat, or house curve, or music preset from my DCX. This is something a sealed designs excel at: Frequency Contouring. Ask TLS, Avaserfi, Ananuki.
I realize that pretty much all subs, in a typical room, can use some eq to get a desireable FR. I was just under the impression that sealed designs, in order to get that FR, tend need it more than ported, due to the generally higher roll off.
I have a DCX in my 2-channel system, the capabilities of which, I still haven't taken full advantage of, because I haven't gotten around to figuring out how. Right now, it's just an expensive HPF and crossover, rather than an inexpensive all-singing, all-dancing EQ.
Some day, I'll have to roll up my sleeves and figure the thing out. I've downloaded REW - still clueless about it.
If I can avoid having to incorporate external EQ into my HT setup, I'd favour that, because head office will be giving the subwoofer project a hairy eyeball with regard to budget. We've spent a big chunk of change on the rec room reno and projector project over the last few months. "Bang for the buck" will be a key phrase for a subwoofer project. Placement behind the false wall will be a
must, which is why I favour 2 subs at 1/4 distance from the sidewalls, in order to help even out the FR.
Then again, one "super-sub", with EQ, could even out the cost of 2 lesser subs....hmmm....just has to fit in the available space. I wonder about the Anti-Mode 8033 - that could simplify EQ.
If it looks like I'm rambling - it's because I
am rambling...