I've had sound problems with cbs for months. the sound is always lower than any other station I have. during commercials the sound changes with each different sponsor. nobody seems to care or they can't figure it out.
Makes me wonder if it's related to my issue where sound will just momentarily drop out on CBS during PTAT recording hours. In my case, changing the channel & returning will restore sound.
Could the problem be with your local station and the signal they send to Dish? I know that here in Rochester NY, the audio level for our local NBC station is significantly lower than any other station on both my OTA signal thru the module on my HWS's and my Dish ota.