Hello. My name is XXXXX XXXXX I'd like to help you with this problem today.
Could you please try plugging the speakers into a device other than the Mac Pro? Perhaps an MP3 player, radio, or cellular phone. Then, try playing music, or some sounds on the device. Do you hear anything via the speakers?
nothing on that either so it looks like a speaker problem
bah, further investigation revealed that there is apower lead and it was out, problem solved
Awesome. I'm happy that we ruled out the Mac Pro. Are the speakers working now?