Sorry if this is the wrong forum, but I didn't see any forum that came closer than audio theory.

Basically, my parents have problem hearing dialog over background music. As they are getting hard of hearing, they naturally turn up the volume. But, the problem is that the background music gets even louder, so the higher volume doesn't really help except to get them frustrated and neighbors annoyed.

Is there a way to get it so that the dialog becomes louder? I've tried the dialog enhancers some DVD players have, but it doesn't seem to help ... does anyone have suggestions?

Get a Spl meter and the Avia Guide to Home Theater dvd and calibrate the system. Chances are that there speakers are not setup right and some of the speakers are over powering each other and drowning out the dialog. If you have a subwoofer it may be set too high and that can realy hurt the dialog. As a last resort try switching to stereo mode or rasing the center channel before rasing the main volume, but if you calibrate everything right with the spl you should have no problem with dialog.

http://www.radioshack.com/sm-digital-display-sound-level-meter--pi-2103667.html

http://www.amazon.com/AVIA-Guide-Home-Theater/dp/630551982X

Are your parents listening to the speakers in the TV or is it a surround sound setup? If they are just listening to the TV don't rush out and buy a meter or test disks. Do take a look at the TV's audio setup menu if there is one. There are sometimes settings to compress the dynamic range and this might help. If the set has some sort of sound processing such as BBE or ersatz surround try turning them on or off and setting different levels.

Have them try sitting very close to the speakers. If that helps you may have problems caused by sound reflecting from walls, floor, or ceiling. There is a lot of info here about treating what are called first reflection points.

I have a 62 year old friend who is suffered a notable hearing loss. He has a surround system, but only uses the center channel and puts the speaker close to him.

Sometimes it helps a bit to change tone control settings; the result may sound bad to you but better to them.

Another way to tell if reflected sound is a problem is to have them cup their hands behind their ears. If that works it is another sign that reflected sound is a problem.

I can still hear past 15,000 Hz (but not by much) and I have room treatments and a balanced system, although the room is still a bit on the live side. Even so with some dialog hands to ears works very well as does moving toward the center speaker.