3D shutter glasses with a synchronization signal sent through a stereo headphone wire are presented. In some embodiments, the 3D shutter glasses receive a synchronization signal through the same wire that transmits audio data to headphones or other audio devices. The synchronization signal may be combined with the audio data through various techniques so as to not disrupt the audio a listener hears, but to still provide the data to the 3D shutter glasses to synchronize with a display.