Facetime audio not working
I've got a Mac Pro with El Capitan (highest compatible OS for my hardware) and I've got USB mic/speakers connected. For a couple years, I've used facetime on my Mac to make and receive calls via my iphone. I recently disconnected them to move my computer and after setting everything back up, the speakers don't work for Facetime. The sound only comes out of some tiny built-in speaker from my tower (the one that makes sound when your computer first turns on). The speakers do work for other apps like when I listen to music. I've also already gone into the sound settings in system preferences and made sure that the output device is the USB speakers. Is there a way to fix the Facebook app or change the sound settings?
Mac Pro, 10.11