Lol...Cwlondon, it sounds like you'll not end up with more dedicated "HT speakers" anytime soon, ey?!!
You know, having sold "quality high end audiophile" speakers over the years, I would say the statement "a good speaker is a good speaker" is about as missleading as it gets really. What a good speaker is, is really different to different people. There are many so called "high end" designs that I should really be classified as "limited application designs" if you ask me. But then again, it stands to reason why many people "in the know" in this biz, consider, if not implement, 2 separate systems for movies and music! They mostly fall in love with something about a particular speaker they use for their fav music(again, probabably stuff like Jazz at the Pawn Shop, Dianna Krall, and similar tempo stuff), and they stay there. These are mostly very pretty, clear, detailed, open, airy, laid back sounding speakers, that do many many things right!...don't get me wrong. In these areas, these speaker "get things right" IMO. ON THE OTHER HAND, when it comes to highly dynamic stuff (often music you don't hear many audiophiles playing much, if any of..except perhaps Correy Greenberg), these speakers aren't so good, and infact fall flat on their faces! They are the antithesis often of what is dynamic, powerful, and anything but flat and squashed out, even at modest levels. In short, the speakers offer limited control over the drivers, inneficient design, low sensitivity, too laid back of a sound in reality, etc! Basically, they lack real dynamic trasparancy to be truely more accurate in this respect! If you think not, just take most any high end audiophile design out there, play some Metcalica, any Techno genre, some hip hop, any heavy drummed up new world, and definitely some overly demanding DD/DTS material through the speakers, and you'll know what I mean...very lackluster mostly.
On the other hand most of the pro audio offerings will stomp the living daylights out of the audiophile kit, even at low volume levels dynamically, and in terms of pressence.
Laidback audiophile speakers make you lean into the sound, and are not so solid and distinct. They're trade-offs here, for certain.
So what speakers do the "balancing/cross-over act" well, and do justice for all? They are rare breads IME. And you should wisely consider if you're trying to "get it all".
But make no mistake, if you're stuck thinking you like the sound from whatever music you heard through some audiophile liking, just remember you're not getting the whole picture.
As for horn speakers, a good horn system can indeed be setup and balanced well with proper gear and system integration. Sounding honkey I guess is all personal. I've owned wonderful sounding (again, depending) Thiels, Sonus Faber, B&W, Infinity, NHT, Merlin, and other speakers over the years, and they all did certain things well. That said, I've rarely had an occasion to call movie theater speaker systems fatiguing personally! Mostly because they're balanced. If anything, a BRIGHT speaker is fatiguing, when the trebble runs too hot. Other than that, maybe the manager has the system turned up way too high, or at THX levels...yes, those guy's at THX are insane! It's too loud, yes.
But, to each his own. I simply find most of what you'll find in the high end houses, marketed as audiophile high end stuff, as really really difficult to get sounding addequately involving and exciting, not to mention effective at reproducing movie soundtracks with any degree of accuracy (from how they were mixed to sound), pressence (exciting), or effectiveness!
Just think how it would sound poping some Maggies up in a giant movie cineplex, and trying to play LOTR's through em! If you can immagine, it would sucketh...IMO of course.
The same will hold true in your large space, trust me.
However, I can understand someone's bad experience with horns. In that case, I would still suggest higher efficiency, more focused, multi-driver arrayed speaker designs, that will focus the sound, maximize dynamics/impact/speed, limit distortion (if not cancel it out completely), and have the pressence and involvement movie mixes were designed to give....not flatten out, obscure dialoge, and sound too polite and laid back. Again, not what movies were mixed through, or designed to play back on. A good speaker is not a "good speaker" here to generalize, I'm sorry. That just doesn't play for quality home theater.
My pick for you to consider, is multiple high end driver Infinity MTS's with 850w/12" powered subs, adding multiple larger subs to the system as well. Another is Wilson Cub's, and matching surrounds around the room, with several, maybe Paradigm Servo 15 subs driving the room. Older Dunlavy SCV's work, with some SCIAV's flanking the room are good candidates on the higher end, but also do movies well (see "widescreen reviews" master reference system).
NHT VT3's on a smaller budget, and matching VS3(?) surrounds is good for the money, and more audiophile clear, if not quite as much resolve as better.
Or MAYBE some of the multi driver Dynaudio stuff is worth a look, with good amplification...but that would be lower on my list for the money...
Anyway, using single woofer/mid and single tweeter designs, ribbon speakers, and similar is not how to do HT, especially on a large room scale! I think you'll lose here.
Anyway, good luck, as there's not really much in the high end that's super super for movies for your application in a large room.
In fact you can pretty much swich out everything in the high end relm, and get the same results for your situation. In that case, I'd get as lest expensive as possible. Otherwise, simply know you're going to have to seriously sacrifice your effective movie sound experience for your musical taste/prefference, and what you've got your mind set on. You mostly won't have it all that way.
Again, hope it turns out well for you however
