60hz

What a DSLR’s Rolling Shutter Does to a Speaker Playing a 61Hz Tone

Here's another example of a strange effect caused by the shutter of a DSLR. YouTube user drummaboy5189 captured the above video by playing a 61Hz sound through his speaker and then pointing his Canon 6D at it while filming at 60 frames per second and 1/4000s shutter speed. What resulted is a "rolling speaker" effect.