Hi TCNCoach,
Welcome to the Heartland Owners Forum and to the family. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.
I would think you should be able to mute, or turn the sound down to nothing on the DVD player and turn the sound up on the TV... That's all I need to do on mine. You might tell us what system you have a maybe someone with the same system can give better instructions. We also have a very good owners manual section under the "Tools" tab at the top of the page.
Enjoy the forum.
Jim M