I have a cooler radio that I take on toobing trips and cook-offs. It is a 40quart with a pair of Polk mm691's, a kac8405, and a 35ah agm battery. I am building a 5 gallon water cooler with a 10 in the lid. I will remove the spigot and replace with a speaker terminal. I will bridge the other 2 ch on the amp and run to a speaker terminal on the cooler. I was looking at Polk subs because they are marine grade. When I want some more bass I will just run the speaker wires from one to the other. I use an iPod direct to the amp. The main purpose of my rig is to make the bikini girls dance on the river. What is the best way to get the max volume out of this setup? Is there a better sub I should look into? Any other ideas to help out?