I would like to use the W3 to make my subwoofer wireless. Can I do this?

Sure. Connect the W3 Sender to the subwoofer outputs on your A/V receiver and then connect the W3 Receiver to the audio inputs on your subwoofer. There are stereo 1/8" mini-jack inputs and outputs on the W3 that will allow you to make an RCA connection with the use of a Y-cable (which is included).