Changing channels can make a loud static sound that can be corrected by switching on "Auto Volume Control".
The crackling sound isn’t the TV. It’s your digital source – like your cable or dish. You need to change the settings from Dolby 5.1 to PCM. When you do, the crackling sound will go away.
The first thing you want to check is the audio setting in the cable box. Make sure the audio is disabled. Secondly, check the audio settings on the TV. Select menu, then audio, select SPDIF TYPE, then chooses PCM. If this does not correct the problem please contact the manufacturer. The manufacturer is aware of this problem. They have created a firmware update to correct the problem. Please call customer service at 1-888-935-8880