I think they 100% react from the sound of the bow, not the arrows hissing as they fly. I watched his video and the whole time I'm thinking that sure quieter is better but I still can't imagine a deer hearing the arrow in flight and reacting as quick as they do. Sure, the sound of the bow, isn't coming much in advance of the sound of the arrow, but it's still the first noise to alert them.
I recorded arrow travel and impact at the target with the solid and vented (wide) head. I can tell a slight difference (at least I think I can) but it’s very subtle.
I asked my wife to listen to both and she thinks I’m crazy. She can’t hear the difference.
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