OK, I tried it on the iMac and the new one still doesn't have sound, the one I've been using has sound on the iMac. I replugged it (the older speaker) into my MacBook Pro and no sound until I shut down and restarted my Mac (again). I can't explain it.
I asked a while back if you tried the speakers with another Mac, and you never said that you did. It may not be helpful, but it will be information.
