Solved! Cant pair two sb3821-c6 sub to one sb3821-c6 soundbar

Solution
If they use bluetooth then it may only be designed to pair with one device meaning one subwoofer.
Using two subs will only raise the maximum volume by 3db (not a huge amount) although having two subs can produce flatter bass if they are positioned correctly. If they are positioned incorrectly you could get cancellation resulting in less bass.
If they use bluetooth then it may only be designed to pair with one device meaning one subwoofer.
Using two subs will only raise the maximum volume by 3db (not a huge amount) although having two subs can produce flatter bass if they are positioned correctly. If they are positioned incorrectly you could get cancellation resulting in less bass.
 
Solution
No need to explain why u need 2, plenty of people do it.

Unfortunately if you are talking about standard Bluetooth, I only know of able to pair one, standard BT can't do multiple pairings.

If these are not standard BT but rather proprietary wireless, well then you are restricted to what the vendor allows.