This is sometimes even more pronounced on a typical HT system with a Cable or Sat box if you compare the volumes of the analog (lower) channels to the digital (generally, upper range) offerings. FWIW, anything coming from my Motorola Comcast DVR box in DD5.1 would have to be really cranked on my Onkyo receiver to be able to hear it properly.
There's really not much you can do in this case, just get a sense of which channels require the volume boost, esp. for visitors using your system ;).
Have samsung ht-3252 home theater-samsung LED tv un55b7100 and motorola dvr(cable service). Volume is good on tv for all channels. When I turn on home theater,on some channels the volume is much lower. I have to adjust the volume when changing channels. Have HDMI cable connected from TV to DVR and HDMI cable connected from Home theater to TV. Also, have optical cable connected from DVR to Home theater.Any suggestions why volume issue?