A set of in-air experiments were made on two, thin, cylindrical shells to understand and control the propagation of membrane waves, which are primary determinants of target strength in the mid-frequency, high-aspect angle regimes. A circumferential source array was used to drive single modes in all wave types, compressional, shear, and flexural. Resulting waves were collected using an axial line array of laser Doppler velocimeter measurements and the wave types separated by array processing. Comparison between a clean plastic shell and a steel shell with a keel-like feature suggest on the order of 10-dB reduction of compressional wave response via coupling into higher order flexural waves by the nonaxisymmetric discontinuity. The conversion coupled with subsequent damping of the resulting flexural waves makes this a potentially useful mechanism for control of membrane waves.