ps i does say on here you need an active sub......
The subwoofer Pre-Output terminal (RCA) can easily connect with any active subwoofer (not included), to get a deep and powerful sound. The soundbar volume is adjusted by the TV volume settings, when connected via the headphone output terminal of any TV-Set so you can use your conventional TV remote control (all brands), to control the volume settings of the soundbar. .................from sharps web page