which result from the application of those stresses to the slab as described below during processing metal plates 14 and 16 are bonded to piezoelectric slab 12 at an elevated temperature the coefficients of thermal expansion and contraction of metal plates 14 and 16 are chosen to be larger than that of piezoelectric slab 12 so that when the transducer cools after bonding piezoelectric slab 12 is held in compression by metal plates 14 and 16 those compressive forces are shown in fig2 by arrows 32 compressive forces 32 not only aid piezoelectric slab 12 in withstanding high hydrostatic pressures but also contribute to a reduction in reorientation of poled dipoles within piezoelectric slab 12 after metal plates 14 and 16 have been bonded to piezoelectric slab 12 the piezoelectric slab is polarized by the application of a high dc field in the direction shown by arrow 34 in fig1 while the structure is held at an elevated temperature upon subsequent cooling compressive forces 32 tend to prevent the dipoles within piezoelectric slab 12 from reorienting away from the vertical alignment created by the applied field as shown in fig3 a plan sectional view taken along line a a in fig1 of a rectangular embodiment of the invention the acoustic transducer 10 can also be configured in rectangular shape while the compressive stresses within a circular piezoelectric slab cause contributions to be made to both the d 31 and d 32 uniaxial piezoelectric coefficients the induced.