Diagnosis
This is often electrical interference, either from a poor-quality audio cable or from having the soundbar's power cable tangled with other cords (like HDMI).
How to Fix It
First, isolate the power. Unplug the soundbar's power cable from the strip or outlet and plug it directly into a wall outlet by itself, away from other plugs. Then, check your audio cable. If you're using the included optical cable, make sure the protective plastic caps are completely off both ends and it's firmly seated. Gently wiggle the cable where it plugs in—if the static changes, the cable might be bad.
If That Didn't Work
Try a different audio input. Switch from HDMI ARC to the optical input, or vice-versa. If the static goes away on one input, the problem is likely with the other port on your TV or the specific cable for that connection.
Heads Up
Never coil up and tie the excess length of the power cord or optical cable behind the soundbar. Keeping it loose prevents internal wire strain that can cause noise.