Second harmonic and fundamental standing‐wave amplitudes have been measured to see if nonlinearity parameters (combinations of third‐order elastic constants) can be determined from measurements made on samples driven at resonance. A model for the resonance is formulated by considering the process of overlap for a sample‐applied pulse whose length is extended to many overlap orders. Attenuation is included in the model, and the nonlinearity parameters obtained from the application of the model to experimental data are compared with values from other experiments.