LG 47LA6200 Owner's Manual page 266

Problem
TV sound is not in sync with
the lips or the sound breaks
up occasionally.
Whenever changing the
channel, the volume is
different.
• If it happens on a certain TV channel, it may be caused
by problems with an individual station's broadcast
signal. Check with the TV station or local cable
operator.
• Depending on the channel, there can be differences in
volume.
• Please set Auto Volume
Solution
to On.