A vibration isolator material manufacturer approached Sound Answers to assist in the development of a test procedure for determining the transmissibility of their material samples. In order to accurately measure the transmissibility of a vibration isolator the isolator must be realistically loaded, as the material properties depend on the static loading of the sample. Sound Answers developed a test setup to measure the transmissibility under various static loads. The TR curves were measured using a modally tuned impact hammer and accelerometer responses on the “ground” and “active” parts of the fixture assembly. The developed method proved to be a simple and accurate process for generating transmissibility curves for rubber isolator materials.