Old Masters Custom Callmakers leads the most distinguished rank of call makers in having Parker Whedon as it's senior member who has contributed the only fundamental improvement ever made in yelpers and suction calls, the slide mechanism of the Crown Trimpet. Not merely a decoration, this mechanism which is described in the patent obtained by Whedon and Hearn, enables the hunter to adjust the basic pitch from higher to lower and lower to higher. It has been copied by another call maker, the patent having expired. Old Masters is further distinguished in having as its other member the multi-talented craftsman Gene Gardner

Suction yelpers, compared to friction callers, are not only more versatile in their inherent ability to mimic a greater range and variety of turkey sounds but also in their ability to transmit in their calls a degree of emotional intensity not achievable by hand manipulated callers. A partial explanation for the difference may be that suction callers are the only ones whose sounds are initially formed by the vibration of living animal tissue, namely, your lips, more capable of transmitting emotional content.