[time-nuts] Striking change in iPhone time accuracy with 8.2
hmurray at megapathdsl.net
Wed Apr 1 16:50:58 EDT 2015
albertson.chris at gmail.com said:
> Sound travels at about 1 foot per ms. So you can effectively delay the click
> on one phone my placing it 8 feet farther away then the other phone.
> Adjust the distance until the clicks seem to occur at the same time. That
> said, I doubt your ears are sensitive enough to work at the single digit ms
Your brain uses the difference in arrival times at your ears to determine
direction. That works better with high frequency clicks rather than low
frequency rumbles. You can work out how good it has to be to get reasonable
results, but it's well below 1 ms.
The usual test case is to jingle some keys. Sit on a stool with your eyes
closed. Have a friend jingle the keys in various locations. Right-left
works well. Up-down doesn't work very well.
It would be fun to play with a pair of beeping iPhones and see what sort of
direction they appear to be coming from. I wonder how much the length of the
beep influences things.
These are my opinions. I hate spam.
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