Seems that this is more of a shutter speed and/or frame rate issue in relation to the frequency of vibration of the speaker, and not a rolling shutter issue.
Still, it is pretty cool! Thanks for sharing.
Edit: On second thought, I think I'm wrong. John is right. I think that rolling shutter is playing a role here, along with the shutter speed and/or frame rate. If not for rolling shutter, the speaker cone should appear to be parallel to the speaker face.
A concept I have been struggling with for the past few years is the idea that the same principle is in effect in reality (rather than a medium live video) when speeds approach or (theoretically) exceed the speed of light. This would imply that our world is happening through some sort of medium rather than simply being a direct reality and the implications would be immense. No, I don't necessarily believe this, but I'm can't objectively rule it out either.
I've gotten to hate rolling shutter effects, and the sad thing is that we are seeing more videos with the rolling shutter. One example was Branson's spacecraft flight a few days ago. One camera view showed everything all wiggly and wobbly. Yuck.
That's great Laurence - in effect, it works a bit like slow motion to show what's really happening.
Although when watching a string plucked "live" we perceive the whole string to be moving left and right at the same time, when you think about it, a tight vibrating string would always start moving from the point it was plucked from, and "pass the motion literally down (and up) the line, just like a ripple.
So there does seem to be a limit to what our eye/brain can "see".
Keep in mind that the guy shot this with an incredibly fast 1/4000 of a second shutter speed. You'd never see this without the fast shutter. I don't know what the shutter speed is on the speaker video, but it must also be very fast.
Peter, the human visual system is capable of complete field updates about 25 times per second. Of course, individual movements faster than this can be detected, but not continuously.
As far as the amount of time it takes to scan and process the entire field of view i'm not sure, but it's probably about half of the "frame" speed, or around 1/50th of a second. I would imagine though that smaller sections of the image are processed in piecemeal at much faster rates.