A:Answer Hi Customer,
You need to pair the subwoofer to soundbar enable to make it work. Please be advise when pairing the subwoofer to the soundbar, make sure that both units are within 3 feet maximum with each other. Check these link for more information.
https://docs.sony.com/release//Manual_4688252121.pdf (page 20 - Activating wireless transmission between specific units)
https://www.sony.com/electronics/support/articles/00138444
Regards,
-David