I have this TV at work.
Please try this and set the Audio to these -
Press Menu button (the one above the center circular buttons)j.
Press the down button until you get to Audio.
Press the OK button (very center button).
Now check that the Bass is set for 0.
Now check that the Treble is set for 0.
Now check that the Balance is set for 0.
If these are not all set for 0, adjust each with the left and/or right arrow buttons (around the center OK button) until each one says 0.
If they are already at 0, simply go down to the Advanced Audio and press the OK button.
Now, the settings here should be -
AI - OFF
Surround - OFF
Bass Boost - OFF
Speakers - ON
You simply go down to each one and toggle on to off with the left and right arrow keys (around the center OK button).
Once you have the TV set this way the audio should be clear. This TV has better audio than most.
Please let me know if you would like more information and/or clarification.