What is ideal dimension size for a home listening room?

brownsfan, I am not aware of any room mode calculators or  mathematical model for rooms with non-parallel walls. We started with a rectangle shape for a base line. Then we did some calcs and made some assumptions to come up with which walls to skew. About 60% of the room is made up of non-parallel walls. About another 20% of the walls are covered with diffusers and broadband absorption. About half of the skewed walls are actually built-in bass traps with reflective surfaces and tuned sections. I can't be absolutely positive we did it 100% correct, but it works great.

I started using non-parallel walls after a learning experience while exhibiting at an audio show in Los Vegas about fifteen years ago. A pair of very large and flat shipping crates placed staggered and skewed along the side wall saved the day.

Non parallel sides, rounded California corners. You probably will settle for less than "ideal."

What’s a California corner?
”ideal” is somewhat subjective and relevant to the objectives.
Please share your experiences with non-parallel walls as used in a dedicated room. I’m always eager to learn.

Anybody live in a geodesic dome?How would a dedicated room work in that circumstance I wonder.

My minimal experience with concave surfaces would suggest very diabolical.