Changing default playback device on Windows 8
I just figured this out myself. If you don't want to restart the program, simply "configure" and "test" the playback device. That is, after setting the default device, click "Configure" toward the bottom left. Click "Test" in the "Speaker Setup" window that appears. Then simply click "Next" twice and "Finish" and you're done. Whatever you're trying to do will now play audio on the desired device.