Vocal Visualizer Use your voice to transform laser light into dazzling patterns. By humming, singing, or talking into the Vocal Visualizer, you’ll be able to see sound as vibration. What’s Going On? When you vocalize, you cause air molecules to vibrate. These vibrating molecules strike the rubber balloon membrane. The membrane vibrates, causing the mirror to wiggle in turn. The laser light bounces off this wiggling mirror, tracing out various shapes and patterns that you can see. (That’s why we call this the Vocal Visualizer!) The different amplitudes and frequencies of the sounds emanating from your mouth cause different shapes and patterns. The harmonic motions traced out by the moving laser beam are called Lissajous patterns. The combination of the mirror moving in an up-and-down direction (along the y-axis) and the side-to-side direction (along the x-axis) create the patterns you see on the screen. Some shapes will look chaotic while others will be more regular and repeating—circles, ovals, figure eights. Various frequencies will cause the rubber membrane to dance around in resonant vibration modes—standing waves of fluctuating hills and valleys on the membrane’s surface. Your mirror and laser also act as an optical lever. If you change the distance from which you broadcast the laser’s reflection, you’ll also change the size of the image that’s projected. Stand closer to your flat surface and the reflected image will be smaller; stand back and the reflected image will be larger. You can achieve a similar effect by experimenting with the volume of your voice—speak or sing loudly into the device and your patterns will be large; speak or sing softly and your pattern will be smaller.

vocal visualizer experiment