The average male vocal folds vibrate 110 times per second (110 Hz) while the average female vocal folds vibrate 220 times per second (220 Hz). Both of these speeds are too fast for the human eye to see, but by using a strobe light during an exam, we can simulate the slow motion vibration.

Notice how my vocal folds vibrate in mirror image to each other at the first pitch, then open for me to take a breath (at the 6 second mark), before starting up again at a higher pitch (at the 8 second mark). The “ripple” you see travel horizontally across each vocal fold is known as the mucosal wave, and demonstrates how the top layer of tissue slides freely over the underlying tissue.