It must be some kind of interference? I figure the wireless sub and the bluetooth on the soundbar operate at same 2.4Ghz frequency as the wifi on the PS4.
Try turning off bluetooth on the soundbar first and see if that works. If you still have issues, try turning off the wireless sub to see if that's the culprit.
Another option is to try using another 2.4Ghz Channel on your router and see if that makes a difference.