I have a Harman Kardon speaker system for my desktop PC which rarely gets any use. It includes a rather large subwoofer (at least it's large as computer speaker systems go). I'm thinking the subwoofer would make a nice addition to my small home theater system. It's rated at 40 watts.
Although my yamaha amp has an output for a powered subwoofer, the level specs don't match. The subwoofer out on my amp is rated at 4 Volts (1.2k ohms) and the input sensitivity on the subwoofer is only rated 400 mV RMS with an input impedance of > 5k ohms.
Is it ok to just drop the output signal using a properly sized variable potentiometer?