It would helpful to provide how the cable box and/or TV is connected to audio device(s). For example: HDMI to TV? Optical from TV to AVR? Analog, optical or coax from STB to AVR? Analog audio (red/white) to TV, etc....
Also, what is the make/model of your AVR?
What is the make/model of your cable STB?
OTOH, I agree with DrDon. If all other channels seem be work properly, it may have been an audio problem with your local feed at that time. IF it happens all the time with only that specific channel.... complain to Comcast.
It's connected hdmi to an Onkyo TX-NR609 then hdmi to tv. I don't know the cable box, it's a basic HD tuner box from comcast. I don't watch too much tv besides sports so I didn't get a dvr one. I think I will just connect hdmi to tv then optical to the Onkyo.