I can only hear certain controllers in x-plane using pilot2atc.  In pilot2atc I can always hear ground controls voices, but I don't hear any other controllers and dont hear their messages, I have to constantly scan for new messages.  I am using the 10 day trial using the latest download.

Depending mostly on your internet speeds, online voices may have a long delay before working or may not work at all.

You can remove all the Online voices on the Voices tab of Settings by deleting them, forcing P2A to use only local voices. 

If you ever want to bring them back, you can just press the "Reload Deleted" button.

Dave