Why are you limiting yourself to sealed speakers?  With a room of that size, there are many options and I wonder why you are imposing such a constraint on your options.

Kal

modification and a pair of Rythmik F12 subwoofers.

http://www.indiespinzone.com/mag/mag4.html

http://www.rythmikaudio.com/F12.html

I think you are projecting your knowledge of the technology onto what you hear.  Almost all the speakers that I have liked/loved are ported designs with tight, extended bass.  In fact, I would suggest that bass performance in the range where the port is making a contribution is more dependent on room placement and acoustics than on the speaker configuration.  "The typical boomy ported effect" is usually heard from cheap speakers (of any configuration) or good speakers (of any configuration) in improper setups. 

That is not to say there are not differences but I cannot correlate them with whether the speaker is ported or not.

Kal

I used to have a bias against ported designs way back when, until I heard some well designed ones.  Every speaker type has limitations, and the implementation must minimize or overcome these limitations.  How successfully that is accomplished has more bearing on the quality of sound than does the weakness of the speaker type in my opinion.  These days, I think the choices of good speakers in sealed design is kind of limited compared to ported types, which have several advantages.
 

A speaker plus subwoofer system may or may not be a more economical way to go for the deepest frequencies. I do think a high quality subwoofer can give greater and more versitile control over the deepest frequencies, but the low frequencies above subwoofer's range are probably more important musically. There are some very well controlled subwoofers out these days, but they are generally not the cheapest. 

An exception may be a friends pair of Rythmik Audio F12SE servo controlled subwoofers (like jackfish) that showed a near perfect output output with sharp cutoff from his setting of 20 - 40 Hz when I measured them. Though my old pair of M&K's aren't too bad either. Note, these subs are set to just fill in the very bottom frequencies.

I wouldn't look at the size by volume of the room.  Is it drywall or plaster?  Horsehair or blueboard?  Acoustical tile or wall material for the ceiling?  Paint or soft, heavy wallpaper?  Lots of small things matter to a greater or lesser extent.  My experience would favor sealed box given first they are large, and second the driver quality is superb.  I had a pair of Sony SS-M3, a very good speaker when I used it with a powerful amp in a fairly small room, biwired, etc. and so on.  In other words in a perfect situation.  Otherwise, they are best suited as rear speakers in an all M theater.  Some of my favorite speakers I've ever owned were an inexpensive set of Paradigm front ported floorstanders.  Superb mid-range, detailed, well balanced bass, and you could practically plop them anywhere and get good sound.

Remember the biggest reason for porting is that it allows the woofer to be loaded (acoustically damped) with a much smaller box.  The joy of a big room is that this is no real concern.  Go ahead and get a big-oh honking sealed box.  The bass will be wonderful, maybe.

That's just just the way the cookie crumbles.

Economical means a lot of different things to a lot of different people.  Particularly in this hobby.  The main difference accoustically between a Sealed vs. Ported speaker is the roll off.  Sealed boxes tend to give you a 12db per octave roll of so realistically nothing will give you legitimate bass in the 40hz range without a huge box or monster drivers and even so most good sealed 2 ways go down to about 60hz effectively.  Ported speakers roll off much more gradually and thus have a much wider Effective Frequency Response.  Sealed enclosures are ideal for integrating with a sub though.  If you prefer the sound of 2.0 listening rather than 2.1 listening, I highly suggest looking for a good ported speaker.  In my experience it is even more difficult and costlier to get a good subwoofer(s) that will integrate well without that tubby sound, than it is to get a ported speaker to not sound tubby (bottom heavy).  I have heard many, many well designed ported speakers that had tremendous balanced, articulate, detailed bass and mid-bass.  I have personally never heard a purely sealed speaker that did great bass below 60-70hz or really any bass at all, but many that produce good mid-bass.

I think what BigRed is saying is mostly true, with the caveat that most disks, even Classical and Hard/Heavy Rock have very little musical information below 50hz, and it diminishes quickly below 40.  Which is basically fine because most people over 25 can barely hear to 35hz/15khz, anyway.  The defacto "standard" of 20hz to 20khz is a bit of marketing.  But.. for another time. 

Having now lived with both, my gut is with sealed, but as has been mentioned, there are very good ported and "hybrid" ported/transmission line designs out there that put a new wheel on the wagon.  

A large high quality ported monitor for example can give you very good bass well into the low 40s, where a good sub integrates well.  I've just never been a fan of subs.

Good luck.

Sealed boxes with 51 1/4" x 14 1/4" x 11 1/2" dimensions and a -3dB low frequency limit of 33Hz. Classic, vintage, but would deliver the goods in a room that size with appropriate power.

My Hales Transcendence 8 towers handle my living space just fine with useable frequency extension down to around 25hz.  I would recommend finding a used pair, but be aware that the company is no longer in existence.  Hence, replacement drivers are not available.

Stereophile reviewed several Hales speaker systems, and some of them are in the archives.

You should look into Legacy Signature SE speakers. They cost around $7,000 depending on the finish you get. http://www.legacyaudio.com/images/made/images/uploads/products/Fronts-Mains/Sapele_Pommele_Signature_SE_web_434_509.jpg

Were those speakers available 2 1/2 years ago when this thread was last active? It's too late now I suspect.

The Legacy Signature has been around for about 20 years, but over the years the speakers have had updated drivers, crossovers etc. The SE version of the Signature has been available since at least 2012 because there is a professional review online if you search the speakers name. Even since then the tweeters have been upgraded about a year ago, but they decided to leave the name the same.

Resurrecting from the dead a very old thread, as this information may help someone in the future.

I believe the speaker you are looking for is the Tyler Acoustic Halo 1

http://www.tyleracoustics.com/Halos.html

These are the many names for the sealed enclosure. The explanation of the latter names is simple. Because the box is air tight, the air inside the cabinet acts like a spring https://www.cleanmaster.onl/