Big, big room -- which 10-20k speakers?

These would be my choice for that room in the $10K range, if available.

Further down the path after living with Tannoys, I subsequently had (2-3yrs with
each) - ProAc Response 4 - ML Prodigy - MG 20.1--drove them using FMA611/ARC
REF600 MKIII + REF3 + dCS stack.

While the MG20.1 had some beautiful natural room filling sound with great staging
(albeit slightly diffused), IME, they lacked that little lower midrange snap, and
midbass punch (dynamic) essential into waking up certain instrumentations to life
(drums, rim shots etc). Bass was big, but weighty they're not (without aid of good
subs). I then reminisced, and missed the good tonality (accuracy/beauty) of my old
Tannoys + valves. Which even with only 50 tube watts pushing, filled my rather large
old room with ease, and had amazing bass to boot which literally shook
door/windows (some serious air they moved!).

Hence, thus far, Tannoy Westminster/Royal, Classic Audio, JBL K2 (Everest - over
budget?) are the few good candidates recommended which I personally feel will slip in
just nicely into your current set-up. Of course, adding a nice little tubed amp, plus
newer source when budget permits later will easily up the ante - Still.. best try to
keep it simple, I'd say.

I can tell you that when I heard the Classic Audio Repro speakers at RMAF in a VERY big room, they could play rock at realistic levels (not earbleed, but real kick-a$$). And remember, the room size we are talking about is almost 21,000 cu ft., more than twice the volume of the 30 x 30 x 12 room that Rtilden referenced. No knock on the Tylers; I've never heard them. Agree w Atmasphere and Johnk that the laws of physics and the logarithmic power/volume relationship pretty much dictate a high efficiency design.

OK, guys, I'm chiming in again here. One day I will try to post photos of my room. I have read many helpful replies from Atmasphere over the years, and I find it hard not to go along with most all of the things he says. And considering his exposure to so much of the possibilities available, I would tend to defer to him. Yep, he's earned his street cred. My exposure is limited, but my listening room is actually a little larger than I had posted, and my Woodmeres do an excellent job with my CODA 15.0 amplifier. How loud do you need, boys? Huh? My spl meter reads 105db or more anytime I want to crank it. But my ears tell me that is not smart. I'm in this for the long haul, and so are my ears. Classical and jazz are my main venues, and I listen as loud as is reasonably practicable, any time I like, and dammit, my room and my seating position are experiencing realistic levels of concert music, at 5-20 rows back in a concert hall, depending upon the recording. Remember, this is my home, and I live in it daily. I do not base my knowledge upon hearing a rig in some showroom one time. I am by no means saying that my results could not be improved by different or larger speakers, but I am very pleased with my system and do not wish for any "more" delivery than I am getting. The OP tasked us with a budget, and I am respecting that. This post is offered only to give some perspective to the OP, from a music lover who listens daily in a rather large room.

Rtilden, Thanks for the comments.

We have done 105 quite comfortably at shows (when things were working) and not been able to manage 95 db (when they weren't).

Even though I rarely play the system that loud, I can comfortably play 115 db at home without the system getting overbearing! I did work on the front end to reduce vibration in the turntable, CDP and preamp to that end. This means that at normal levels the system is utterly without strain!

Getting a relaxed sound is the key. Especially if its relaxed at high volumes. IMO/IME a system should never sound loud. You should be surprised that you have to yell for someone sitting next to you to hear you. If OTOH the system sounds loud and shouty when you turn it up there is a problem somewhere- something that is generating odd-ordered harmonics (microphonics, resonance, cone breakups, amp clipping etc.).

Mapman quoted something on a different thread which I am paraphrasing- 'It is THE luxury of high end audio to listen at high volumes without stress'. That's it in a nutshell and is why efficiency is indicated in this situation.