Samsung PL64E8000GFXZP - Manual (Page 101)

External Speaker , the TV’s speakers
are turned off. You will hear sound
through the external speakers only.
When the Speaker Select is set to TV
Speaker , both the TV’s speakers and
the external speakers are on. You
will hear sound through both.
N When the Speaker Select is set to
External Speaker , the volume buttons
and mute function will not operate
and the sound settings will be