Acoustic‐surface‐wave convolution by nonlinear mixing has been observed in cubic, hexagonal, and trigonal crystals. The magnitudes of the phenomenological nonlinear surface‐wave coupling constants are tabulated and compared with the linear electromechanical coupling factor 2(&Dgr;V/V). It has been found that the basal plane of PZT‐8 has a larger nonlinear coupling constant than that of the commonly usedY‐cutZ‐propagating LiNbO3.