A theory has been formulated by Dr. G. W. Stewart by which it is possible to determine the selective transmission in three types of specially constructed acoustic wave filters. The theoretical attenuation factor also has been worked out and shows fair agreement with experimental results. Theoretical values of the attenuation were computed for one filter of each type and, from these values, the theoretical transmission curves were determined. The types of filters were the low-frequency and high-frequency— pass, and the single band
