Here are some various pictures of some of the traces of the Schaefer-Bergmann patterns, my notebook, The patterns themselves etc.. (I have better pictures of the patterns on my digital camera and in my power point presentation.

Images of the main longitudinal sound wave imaged with a 4f Fourier set-up the undeflected beam and the diffracted orders greater than m=1 are filtered out at the spectrum plane. Notice the change in the pattern as it moves from left to right, (transducer to absorber) the Fresnal number changes due to diffraction of sound wave).