I tried adding amplification to the existing 8" concertone sub in my Rockwood.
Just a simple 50 watt amp with built in adjustable crossover. I pulled a #10 wire from the battery to the amp location in the cabinet that houses the sub.
It Will Not Work. The 12v system will not handle the power drain. The 12v converter is not high enough amperage to handle the current draw. Everytime the bass hit, the lights in the trailer dimmed. So I added a 1farad Cap to the power line to try and smooth out the power drain. It worked for a few minutes, but the lights kept getting dimmer and dimmer.
Yes, I checked the battery. It is a 3 mth old Interstate.
My solution was to remove the Concertone sub, install a high level to low level converter on the exisiting speaker leads and install a small home theater sub, a Velodyne Impact Mini Velodyne
. It fit in the existing cabinet, and WOW what a sound difference. And since it runs on 110v, no problem with the 12v.
Only down side is it does not work without shore power.
Your mileage my vary, but it worked for me.
I will try and take some pics soon......