HDTV Visio Volume issue

Question

I have a Vizio HDTV 720p 43inch conected with HDMI cable to comcast HD/DVR on HDMI 1 and an Upconvert DVD on HDMI2. the sound sucks. The only sound options I can see are HD and on/off. I cant believe these TVs dont have smart sound. Anyway the sound on regular tv shows isnt too bad but watching any type of movie is brutal. Either through the HD/DVR or the DVD I have to put the volume to 60 and still can hardly hear the dialogue, then get blasted with any kind of sound affects. So my movies get watched with the remote in hand..up to 60 down to 30 up to 60 down to 30...the whole d**n time. Can you give any suggestions for set up please save my sanity!