is too large a room no good?

Most speakers are designed with the emphasis on good on-axis response, with the expectation that they will be listened to from close enough that the first-arrival sound will dominate over the reverberant energy as far as tonal balance goes.

But in a very large room, assuming you listen from fairly far away, the reverberant energy will dominate the tonal balance. In that sort of situation, the speaker's power response (summed omnidirectional response) will matter more than its on-axis response. Far more.

My first sobering encounter with the importance of power response in a large room came back in the late 80's, when I took my killer homebrew speakers to a small-scale dance that was held in a back room at a church (about twice the size of your future room). I was very excited about showing off my talent. The speakers had a 15" woofer, 7" midrange and 1" dome tweeter. Well, they sounded like crap in that room! I was truly horrified, and had no explanation (the concepts in the first two paragraphs above were unknown to me at that time).

The answer would have been speakers with good radiation pattern control. That's one of the reasons prosound speakers are configured the way they are (big woofers, big horns) - not only does that give high output, but it gives decent radiation pattern control, and that's what works in a big space.

The Sunny Cable speakers you mention are like high-end variations on a prosound-ish theme. They almost certainly have a much smoother power response than conventional direct-radiator speakers, mainly because horns do a good job of radiation pattern control - which relates directly to the power response - which relates directly to the tonal balance in a very large room.

There are other ways to get good power response, but a high quality horn-type system is among the front-runners for a very large room in my opinion.

Duke
dealer/manufacturer

I think horns would be just about your only choice in a room like that. Otherwise, power requirements will really get out of hand. I personally prefer small rooms because you can load them just right without having to resort to anything crazy. I hear great things about top-end JBLs, but they sure aren't cheap.

Arthur

I too have a large challenging room 18 X 31 with 12 ft peak open beam ceiling, tile floors over concrete, lots of glass, plus an open stair well up/down.

If possible, position the speakers along the short wall. If not, then midway (or less) and fire towards a wall, not into the room. Alas, I have to fire into the long wall.

I found big speakers (lots of radiating area) to couple best. Currently biamping Magnepan 3.5Rs with Wyred4Sound multichannel amp, plus a SVS powered sub.

Getting great sound will definitely keep you busy, but hey, it's a hobby

I used ATC SCM 20 and a sub in a room with space for a complete badminton court, hot tub and large ornamental fig tree. Approx dimensions were 50 feet by 36 feet with 11 to 18 feet vaulted ceiling. No problem at all to fill this space (but I absolutely needed the sub) and I like to listen extremely loud - everything was wood with windows along two sides...not the best of acoustics due to the reflective gymn floor.

So if you get speakers with very wide and even dispersion that play at pro SPL levels with low distortion then they will fill any space well (won't fix reverberation issues but will fill the space evenly).

Without naming names (and upsetting owners), my experience with these small ATC bookshelf speakers compared to several other brands of consumer speakers (big well known names) caused me to radically change my opinion about non pro designs with non-pro drivers. Today I would not use anything but a pro design in a large space.

I agree with Aball, I think horns are by far your best choice in a room of that size. You could come up with some other set-ups that would work, but the horns will be much more energy efficient.