Mechanoelectrical transformations are studied on models with different geometries and piezoelectric inclusion concentrations. The electrical signal intensity is found to decrease with increasing depth of a piezoelectric source relative to the position of an electrical signal detector. The electrical signal is the difference between signals from the unlikely charged surfaces of the piezoelectric source being deformed by an acoustic excitation wave. The spectral amplitudes of electrical signals coming from different regions of one sample and from identical (in composition) samples containing a large amount of piezoelectric inclusions differ considerably. This difference is due to the random orientation of the quartz piezoelectric axes relative to the electrical detector. Therefore, nondestructive mechanoelectrical techniques for inspection of heterogeneous materials with piezoelectric inclusions must use amplitude-independent criteria.