The particle velocity profileV(ρ) across the face of a transmitting transducer is shown to have large effects upon the diffraction loss and phase change in the ultrasonic field of the transducer. Various functionsV(ρ), monotonic decreasing from the center to the rim of a circular transducer, were employed. The pulse‐echo response of the transducer was calculated by numerical integration on an electronic computer. It was found that the functionsV(ρ) chosen caused the diffraction‐loss and phase‐change curves to be smoother than in the piston case and caused the respective peaks and plateaus to shift with distance in the Fresnel region.