Listening "Volume" would be a more precise way for rooms to be compared.
Small speakers may seem lost in your space.
What do you have now?
Seems to me you are listening in a nearfield environment much like I do in a smaller 16x21x10 room with two large openings to other areas.
Are your current speakers failing in some way in that location in a nearfield environment? Or, are you looking for a bit 'more volume or substance' for the entire large space when listening in the background. Larger might be better then.
I'd sure suggest a 4-sub Dist Bass Array to help the space's bass and boost the extreme low end. More details please. It's an interesting question.
It is a strange situation and my current hypothesis is that my amplifier is underpowered. There's just not enough substance in the room. The sound seems stuck in the speaker and not filling the room. Strangely, if I go into the den, which is a separate room with just a door opening to the great room, the sound is somehow better.
There is one sub-woofer on the system now. A REL Strata II.
One of the typical questions I get asked when auditioning speakers is, "what size is your listening room." So yes, I am interested in being able to answer that question.
I'm trying to determine how to get a better sound. I'm not sure if the issue is the amp, the speakers, or the placement.
For concentrated listening, I'm happy to stick with the "designed" listening spot, but I do have music playing all day long, so am also casually listening in every room.