Open floor plans should be treated as a single volume, but since you're sitting closer to the loudspeakers within that volume, you don't necessarily have to upsize all the audio components. But if you like it loud, err on the side of more power and bigger speakers.

And Mojo, I'm detecting blank spots on the wall awaiting the next candidate weapon. May I suggest:

https://www.amazon.ca/GURPS-Ultra-Tech-David-L-Pulver/dp/1556349718

(I somehow have the first edition written 30 years ago, sitting with some of my Mike Pondsmith RPG's).

Author of "Status 101: How To Keep Up In A World That Keeps Score While Buying Into Buying Less"