I have a USB with music file but my subwoofer will not play. Aquatic AV July 16, 2020 20:01 Updated Make sure that your music file is in MP3 format and the USB drive is no bigger than 32GB. If not, the unit will not read. Related articles What kind of outputs do your subwoofers have? What is the difference between SWA6 and the SWA6+? Comments 0 comments Article is closed for comments.