Sound systems for people with nerve damage

I have what the doctors tell me is high frequency nerve damage. And i have learned that this is common in people over 55 years of and anyone exposed to loud noise.

I cannot understand the dialog on TV programs and movies on two of my three TV's. But I can just barely understand the dialog on an old TV that I have in my bedroom. The old TV works when i move it to my living room. On my two TV's that I have trouble with, though they are loud I can understand dialog on commercials even when I turn the volume down. Music from Direct TV is also easy to understand. I want to buy a new flat screen TV and I have the same trouble with them in the stores. The salesmen in stores like Best Buy and HH Greg say a home theater system is all I need, but I can tell that they don't understand my problem.

The actors sound like they have food in their mouth along with slurring their speech. Plus they sound kinda like they are in a barrel or tunnel with background noise or echo.

Can I buy a sound systems, theater systems etc that will give me the same type of quality sound that I can understand that I now get from the old TV in the bedroom?

If I understand the problem correctly try this. Go to the menu on one of your newer tvs and adjust the sound settings. Pull down the treble and bump up the mids and bass see if that helps.