Dynaudio Audience 72 vs. 72SE

Agree that the Onkyo and 72 series will be fine in a large room.

The 72SE also has a Contour S tweeter. A much more sophisticated speaker system overall than the 72 in the same relatively plain wrapper.

The Onkyo will likely not get the most out of the SE's, but they would provide you with speakers your system could "grow into" if you plan to upgrade electronics in the future.

I believe the SE's use woofers from the old Contour line v/s the ones from the Audience line. That woofer is capable of more subtle sound and detail but will "bottom out" at very high power with a scary "Wackk" sound. As long as you don't drive it way too hard with a powerfull amp like Bryston no issues. This is based on my experience with a Contour 1.8 Mark II. Never had this issue with both my Audience speakers (50 and 52's).

The SE may also have an upgraded cross over for improved sound but in the standard 72 enclosure.

Whats different? I'm not familiar with the audience except I had some loaner 42's. They are out of production but found this on Dyn's web site.
http://www.dynaudio.com/eng/systems/lines/audience/72se.php
Either should be just fine for your room.

Those will do just fine.