If you're not getting audio through your Slingbox M1, please verify that you have the red and white audio cables hooked up between the Slingbox and set-top box in addition to the red, blue and green HD video cables. For further information on troubleshooting no audio issues, I have linked a knowledge base article below:
Sling Media Forum Moderation Team
Thanks. I do have a solution. I have two HD boxes. One contains a DVR the other does not. My original problem occurred when I tried to connect to the M1 to the DVR box i.e. video but no audio. Later I tried connecting the M1 my other HD box without the DVR. Everything worked perfectly. I called Cogeco, my cable provider, and told them the audio out was not working on the Pace RNG200N. They sent a fix and rebooted the Box. Now both the Audio and Video aspects of the Slingbox are working on both my Windows Desktop and android phone.