I have a Bose Soundbar 120 system and a Vizio M55-C2 tv. When I go to the tv and use one of the smart apps (Netflix/Amazon) I have audio coming from the App and the cable box. How do I silence the satellite box audio when using the smart tv apps?
Depends on how you have to equipment connected.
The easiest way to connect the system is to have the sat box connected to the TV via HDMI. Connect the soundbar to the TV with optical audio. That way whatever audio plays through the TV will play through the soundbar.
You can turn the TV speakers off or turn the TV volume down (it won't affect the sound coming from the Bose).
If the sat box is connected directly to the Bose turn it off when you want app sound only on the TV speakers.