Speakers for a Large Room (20’x37’)

I've got a big room thats L shaped but pretty much open.  A stairwell seperates the front wall leaving corners about 18ft apart.  The back wall is a little over 30ft long.  If you've got corners you can easily fill the room with a huge natural sounding soundstage with any amp (I'm using a 2 watt SET) and can reach 90db with more to go. 

Corner horns while large don't really take up much of your living space unlike standalones that need to be away from the front wall.  

Imagine Cornwalls with a bigger fuller sound.

To answer a couple of questions, my ceiling is 10', and I listen mostly at low to moderate volume levels.  The need for a speaker that plays really loudly is low priority.  
@islandmandan You say your Tannoys are custom but I wonder if you could equate them to the Ardens,or perhaps a larger model.

@yyzsantabarbara  Thanks for the pointer to the Yamaha NS5000.  I'll do some research.

My main space is 45x25x16 broken up into LR, kitchen, and DR. My Zu Def 4 speakers are on the short wall and effortlessly fill the space using only a 300b SET. In my experience a high efficiency speaker is desirable in a huge space. 

Yamaha NS5000 for a home demo:

Yamaha - NS-5000 3-Way Bookshelf Speakers with Stands (musicdirect.com)

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Flagship Hi-Fi 5000 Series - Yamaha USA

NS-5000 - Overview - Speakers - Audio & Visual - Products - Yamaha - United States

I'm sorry @danager  but I missed seeing which speakers you were referring to.

@fiesta75 Thanks for the reference to the JBL Everest.  Lots os folks thought it was the bestof show at the recent CAF.