Looking for new speakers for large audio room

I second the vandersteen Kentos. They have built in powered sub and I think your Pass is enough to drive them. It could be though that you have a twofold problem. Even with the high efficiency system you have, the room may just be too big. You might need more power. 

@geof3 

How does the stereo sub line array differ from the DBA where you place them around the room? Does the line array work like the DBA in canceling out room modes? Thanks 

Ron 

Edit: my ceiling works as a baffle with wood going across if it’s affecting the bass.

cant Demo the vandersteen the dealer can only order them;)

Common clearthinker, why not!

Given you amplifier's power I think  Atma sphere's recommendation makes the most sense. Without a line source dipole I think horns will work best. However, with subwoofers your amp will drive Sound Labs 845's but you would need two more subwoofers for it to work really well.
I use JC 1's which are Class A to 25 watts and I rarely use more than that. I also believe your Pass will push a lot more power just not in class A.

Hello,
+1 for the extra subwoofers. If you are not going to go that route I would go with one of the KEF blade 2s. They have side firing woofers that creat a ton of bass. If you don’t believe me go listen to a pair in a room half the size. These things need breathing room and you have it. Also, with such a big room you want the music to sound good outside of the perfect listening chair. These do it in spades. I love the KEF Reference 5s. You would be better off with the blades. KEF has a subwoofer, The KC62 that plays down to 11hz in a one foot square box. It’s like having two of these awesome subwoofers in each speaker. I don’t own KEF Blades but I have heard them at a brick and mortar store close to me. https://holmaudio.com/This store lets you try stuff out in your home on your equipment for free. No buyers remorse. I hope this helped you out.