Thanks for using our online forums! I'm sorry to hear that you're having this audio issue with your Slingbox/ SlingPlayer for iPad. Is the volume turned up on the iPad itself? Regarding the message "Audio Device is in Use", are you using external speakers or anything like that on your iPad? Are you able to get sound from any other source besides the SlingPlayer on the same iPad? Do you get audio if you access your Slingbox on Watch on Slingbox.com on either a PC or MAC? Have you tried another set of audio cables from your cable box to your Slingbox, and made sure they are coming from the outputs of the cable box and into the inputs of Slingbox?
Here is an article from our support site regarding audio issues:
And with the Slingbox, the cable box doesn't necessarily have to be powered on all the time. It does, however, need to be on in order for the Slingbox to stream video from it. The cable box is the video source, so just as it must be on when you are at home in front of your TV, it also needs to be on in order to view the video from it when accessing your Slingbox. You can power your cable box on by pulling up the virtual remote within SlingPlayer for iPad, this will function and control your cable box just like your physical remote would at home.
Here is a link from Slingbox.com with some additional information about remote viewing and the virtual SlingRemote:
Hope this helps!
The Sling Moderation Team