I too got myself a NAXA 19" 12 volt 1080p TV/DVD and media player for the cargo trailer and I was pleased to find the video quality is superb, but the sound via the internal speakers was appallingly tinny, aenemic and just plain bad.
So in the effort to improve it I bought a cheap 12 volt stereo amp like this one
http://www.ebay.com/itm/Mini-Hi-Fi-Audi ... 4aad2cad5e
and hooked it to a couple of small 2 way accessory speakers in bracket equipped enclosures.
I'm here to tell you the sound this simple and inexpensive setup creates is just astonishing,
Especially considering the very small cost and effort! There is absolutely no comparison to the TV's speakers. To boot, the TV's 'surround sound' setting actually does what it claims now.
It draws only a max of 28 watts and is usually well below that.
The amp can be found cheaper yet, on eBay with a bit of searching.
I found that the provided wall mount threaded inserts in the rear of the plastic case,(That has a lot of slots in it to aide cooling the electronics) while good enough to hang the set on a wall in a building, did not seem robust enough to resist the chance of the case breaking from the shaking of the sets mass as a moving trailer encounters bumps in the road.
I mounted the TV from the ceiling on a hinged bracket I made, so that the set lays on its back for travel and swings down for viewing. (Quite comfortably from the bed!)
