A cork wedge will dry out over time, losing its elasticity and ability to hold the reed tightly against the tone board. "When that happens, the call will lose its crispness," Gaston says. "Callers should replace the cork wedge periodically so the wedge-reed contact will be tight and the call will remain crisp-sounding."
Barrel thickness is another important factor influencing a call's tone. The thicker the barrel, the more vibration it will absorb. This means that a call with a thicker barrel will have a slightly deeper, mellower tone, while a call with a thinner barrel will have a higher, edgier tone. Other factors that contribute to the way a call sounds include the number of reeds (single or double), the diameter of the call's tone channel (where air exits the insert), the length of the tone board, and the tip of the reed's position relative to the slope of the tone board.
In addition, there's the matter of how a particular caller actually blows the call. "Some people blow harder than others. Some folks cup the call with their hand and use their fingers differently. There are many factors that determine what kind of sounds come out the end of a duck call," Gaston says.
Calls made of acrylic typically produce sound that's sharper and louder than those made of wood or polycarbonate. Top-quality acrylic calls have other benefits as well. They are nonporous, whereas wooden calls will absorb moisture and then swell, mainly on the inside of the call. This increases pressure on the insert and changes the tone of the call so that it isn't as sharp as it once was. Overall, acrylic calls are more consistent in the sounds they produce under various hunting conditions.
"If you really want a call specifically geared toward your needs and calling ability, find a custom call maker whose calls you like, and go visit him in his shop
," Gaston advises. "Tell him what you're looking for in a call. Let him listen to you blow. Then he can fine-tune a call to your specifications."