Does the speaker volume control/remote also control the volume on an external powered subwoofer?
No, the speaker volume control on the ZVOX 315, Mini and 325 will only control the master volume of the speaker itself. It sends a full-range fixed output to an external powered subwoofer. If you use a powered sub with those models, you’ll have to control the sub’s volume on the subwoofer itself. The ZVOX 415 and 425 use a variable sub out so their volume/remotes will vary the subwoofer volume as well as the main speakers’.