I am in the process of building a portable 12v battery powered boombox. I am using a cheap 2.1 channel amplifier board, "KKmoon TPA3116D2", with 2x50 watt left and right channels and a 100 watt subwoofer channel. I need the subwoofer to be 10 inches, however, i cannot find a 10 inch subwoofer...