Every now and again, my max will be sans audio while watching a video on YouTube or from a website. Seems that a reboot brings the audio back. Then I had an idea, sure enough it worked for me 2 times now. Plug a pair of head phones into the jack, then unplug them. Like magic, you got sound. If moto doesn't fix this problem, I'm gonna market a key chain earphone plug just for this (hope you read that with the sarcasm it was typed with)
Hope this helps
Hope this helps