Seat system resonant frequencies play an important role in seat design and ride dynamics. These frequencies can be evaluated with a hydraulic shaker table using either a swept sine or road load input, and through resonant impact and modal analyses. Each testing method provides specific information about a seat's dynamic characteristics. Due to the non-linear nature of automobile seating systems, it is necessary to address the differences between these methods. This paper presents a practical approach to understanding these varied methods for determining dynamic resonant characteristics and synthesizing the data from each method to produce a comprehensive dynamic model.