atlas:

In 30-degree moist weather, the speed of sound is roughly 1100+ fps. Let us pretend your shaft is burning in at 300 fps. Which will reach the deer first? Remember, there are post-release sounds also.

http://www.edersbow.com/publication/...sk/default.cfm

Of course, I have to consider that you have not yet observed many deer react to sounds when bowhunting, at common bowhunting ranges. In time, you may eventually see how fast a deer can react.