Thanks for posting to our Forums! I understand that you that you're Slingbox 350 is not playing any audio.
In this situation I would like to ask a few questions. Is your Slingbox 350 connect to a TV, if so does the TV play audio? Have you tried another set of audio cables(Red and White cables)?
In the mean time, one thing I would do is make sure the cables and cable box are working correctly. To do this all you need to do is disconnect you cables from the Slingbox, and then plug them into a TV. Basically bypassing the Slingbox. If you get audio there is going to be an issue with the Slingbox that will need to be addressed, If you do not get audio then the issue will be with your cable box or the cables you are using.
Hope this helps!
The Sling Media Moderation Team
Sorry for the late update but I found out the issue afterall and I just want to share incase anyone have similiar issues. It turns out it IS my Comcast and DVR settings!! There is submenu within my Mororola DVR that you can setup audio output as Stereo. I previously tried to correct this on the service menu (harder route) instead but it didnt do anything.
But yes simply setting it to "Stereo" apparently did the trick and I'm able to get full clear audio I used to get again. Thanks Zbonomo12 for the prompt respond, I really appreciate the help.