[Wayne A. Pflughaupt]

I decided to go sub crawling after brucek stated "haven't had this situation before" . I tried locations between the chair and the fireplace, On the hearth of the fireplace, in the entry, to the right side of the couch and ended up as shown in the sketch, to the right side of the components' rack. Driver towards the wall about 5 inches away.

Here is that graph:

Aamzing. It’s not often you see improved performance with the sb out of a corner. I just confirmed it again here at my place. I would have expected that open hallway right next to the sub to annihilate extension. But - the graphs don’t lie!

Any suggestions on room treatments or is size reduction the only option?

What low frequency treatments primarily do is reduce ringing (a.k.a. long decay times), similar to what carpet and heavy curtains do to high frequencies. They can’t improve SPL or extension.

Regards,
Wayne