a transducer diaphragm comprising a diaphragm plate with a predetermined pattern of recesses and mesas formed by a chemical etching method to change and / or isolate the expansion and contraction areas of the plate under pressure . in the illustrated embodiment , the pattern includes a central depression on the rearward face including peripheral cutouts extending outwardly from the central depression to receive a strain gauge , thereby positioning the location of the maximum compression amplitude of the diaphragm to be under the gauge .