If your Samsung TV is connected to a home theater system, you probably want to use the external speakers for sound. External speakers give better sound quality than the TV's internal speakers. If you use the mute button to silence the speakers, the TV will display a icon or message on the screen warning you that the sound is muted. If you want to mute the sound without the warning temporarily, just turn down the volume. To mute the sound long term, disable the internal speaker through the TV's menu.
Press the "MENU" button on the remote to display the main menu on your Samsung TV.
Highlight "SOUND" using the directional buttons.
Press the "ENTER" button.
Highlight "Speaker Select," and set it to "External Speaker."
Press the "EXIT" button to exit the menu.