I have a Denon AVR-884 running my 5.1 garage TV set up. I have a decent TV 20' coaxial cable going from the audio out to my TV input on the receive. My question is why is the tuner an CD volume levels so much louder at lower volume levels then the TV setting for which sounds great for quality but I have to turn it way up over the other audio volume levels to get it to come into good sounding levels. Any basic reason for this or the length of my TV audio cable causing this?

All my TV theater set ups in my house use HDMI cables an all functions TV, DVD,CD sound like the same volume level when switching between them an wounded if it's the HDMI over my coaxial cable garage set up causing the lack of volume? I don't want to be watching TV at a high volume level an then someone switches to tuner an blows the speakers. Any input would be greatly appreciated.