Our archery hunting crew has used grunt calls for over 30 years. We have tried a number of big name and custom made calls. They all have different levels of sound and volume. What we have learned is to have a call that you can "reach out" with if the buck is a ways away without the call "quacking". When you get the volume and pitch to the buck, whatever distance, and he reacts, call quietly 1 or 2 more times then wait. If he heard you he is either going to ignore you, come right away or sneak in later looking for the buck that made the call. You never know as each animal is different in the way they react. A grunt call is definitely in our reach every time we are after a buck. Does seem to shy away from a grunt call. They must think it's a horny old buck that they're not interested in just yet.