Thanks for reaching out to us here in our answers forum! I'm sorry to hear you're having an issue with the audio through your Slingbox. I would first recommend checking the cable connections and the cables themselves (Red & White audio). If the issue persists any further, I would advise testing the cables and the output from your cable box. This can be done by connecting directly to your TV with the same cables and from the same output from your cable box.
Here is a link from our support site with some additional information regarding the issue you are describing as well:
Hope this helps!
The Sling Moderation Team
My slingbox-hd was working fine for months and then suddenly the remote was unrepsosnive. after re-booting the slingbox, the remote worked again - except for the audio. none of the cable connections have changed and i tried re-booting again but still no sound.
appreciate the help - was unable to start a new thread.