While a quiet bow may help, deer can still react to the sound before most arrows can get to them. However, we're talking about alert,suspicious deer. I've never seen a relaxed deer "jump the string" when I shot. One's that suspect something are famous for it. In this case, you should aim for the bottom of the kill zone (if at all) so that if the deer drops, your arrow likely will still be in the kill zone. It's worked several times for me.