[6ren]

nice point, but they'd synchronize with an offset. I doubt absolute time would be used to synchronize the videos anyway; they'd be matched by content.

Or do you mean that different frequencies will travel at different speeds, enough to make (e.g.) high and low frequencies arrive at different times? Whoa, apparently it does (http://en.wikipedia.org/wiki/Speed_of_sound#Effect_of_freque...) but seems to be a small effect.

[JonnieCache]

When setting up a big sound system, you have to delay the bassbins by up to 10ms, depending on the size of the cabinets.

Also, how do you calculate your offset? Consider that it is constantly changing.