Norty, it is a very easy job to replace the overhead speakers with better ones. I got some nice Pioneer speakers for $60 a set and they really woke things up! The wiring Jayco used is fine.
Later, I put more JL speakers in floor at front of cab and a large JL sub woofer along with a JL marine amp. Movies are loud and clear and the bombs in war movies will make you duck!!
The guys at the stereo shop laughed when they saw the speakers Jayco installed and told me they are $2 speakers then showed me some in a catalog.
Now, I went completely overboard because I like music but my point is for only a few bucks and 30 minutes with a screwdriver you can make the TV sound great. Simple job.
2015 Jayco Precept 35UN
Towing JEEP TJ with Roadmaster plates and bar w/Blue Ox Patriot brake
an Aluma low bed trailer with HD Road King and/or Polaris RZR onboard