1. Make sure your volume is up, which I know you've seen to it. I just had to mention that first.

That said, I noticed that the voice turn commands only kick in on the most obvious turns. I took mine for a spin today. My trip had 5 turns and it only called 3 of them. I'm not entirely sure why. The path was marked correctly on the 810 but for whatever reason, I didn't always receive a voice prompting.