My jbl bar 5.1 10 inch subwoofer keeps making this crackling noise even when there is no sound playing from any device just on.
Is it a sudden burst of white noise or a constant crackling? If it's a constant crackle, it could be a faulty cable or connection..
It seems to come and go but lately alot more than not and sounds like it's getting louder.
Try changing the wire that connects the soundbar to the sub...
Sounds like a fault has developed then if it's only started recently.
I assume it was supplied by BT so if it's still under warranty, you'll need to get in touch with BT to discuss a repair or replacement under warranty.