I know you guys are way above my head on whats works but my OFF-ROAD POPUP Jensen Radio/DVD stereo speakers do a great job.
These are mounted in the outside wall just above the tire location. Inside it is very close to where the JENSEN radio is installed. My simple system uses the JENSEN front/rear slider switch for inside trailer and outside trailer speakers... I try not to bother the other campers but do like to sit and listen to my country music when sitting around the camp fire...
This is where my JENSEN radio is installed and you can see the inside stereo speakers in the wrap around seating underseat storage areas.
The outside stereo speakers are 5-6 inch size and are the weatherproof style. Sounds pretty good under the patio awning...