I'm only getting audio on one side! (Mac)
Sometimes an update to your Mac operating system can throw off your audio settings. Go to your Applications folder and choose the Utilities folder. Inside Utilities, choose Audio/MIDI setup.
Change "Properties For" to radio SHARK and take a look at the audio settings. They may have changed from 44100.0 Hz and 2ch-16bit to something else. For example, if the format is 1ch, that means "1 channel," which is why you are hearing a "mono" output. Just change them back to their proper values and you should hear a stereo output again.