I've had an account with Google Voice since its beginning; I had an account with Grand Central before Google bought it. I couldn't make a call yesterday. Firefox wouldn't transmit audio. The 'audio settings' showed a response to speech but neither test sound was audible. I called a friend, who heard nothing nor did I hear him. I could record a greeting and listen to it, which I would imagine use the same facilities. voice.google.com has permission to use the microphone. I tried 2 separate sets of audio hardware. After futzing with it for a day I tried Opera, which worked without a hitch.