I have a pair of USB headphones that I keep connected to my Mac all of the time. I also have a nice pair of speakers, and I switch between the speakers and headphones, depending on what I’m doing and if anyone else is home. Having to open System {references to change inputs every time is a bit of a pain, but there is an easier way to do it—our friend the Option key saves the day again.

1) Hold down the option key and click the Volume icon in the menubar.
2) Select the name of the input or output you want to use. (In some cases where you have multiple USB inputs/outputs they may have some interesting names.)

The input switcher isn’t just for audio devices connected directly to the computer; it lets you switch to an AirPlay device on your home network as well.