Different audio levels, same settings

[Drecon]

Ok, so my problem is that depending on what I'm watching,either television or dvd/blu-ray, my audio levels are different without changing any settings. My television is louder than my dvds and blu-rays. I have a Panasonic 50" Plasma 720p HDTV. Hooked to that via hdmi cables are both my cable box and my Magnavox NB500MG1F blu-ray player. From the television via an optical cable my audio is routed to a RCA RT2770 home theater system. I don't use the television speakers as they cause an echo, but while watching cable the hts is kept between 20-25. Then when I put in a movie, I have to crank the hts up to 41 which is max. Even then, if the characters whisper, it is hard to hear them. I could go back to rca cables or even component cables and get louder volume, but I enjoy being able to just have one remote and not have to get up to swith the hts setting when switching between a movie or regular television. Can anyone explain why the difference in volume levels without changes made to any settings?

[Spiky]

Because the volume is set to different levels in the source material. You may even find different channels to be vastly different through the same cable box. FX was always the annoying one for me, ridiculously lower than almost any other channel. Or I'd flip between my local Fox and CBS football games on Sunday and there was a 10db change.