To analyze systematically the response of quartz crystal resonators (QCRs) in electrolytes, a set of experiments was performed with well controlled variations in material and experimental conditions. Three acoustic resonator configurations have been used. The sensor response in each configuration is reproducible; however, the results confirm the expected dependence of frequency shift and resistance change on the experimental setup. The extraordinary contributions to the sensor signal can be attributed to liquid conductivity and permittivity, parameters which are not considered in the common understanding of the transduction principle of QCRs. The effects measured contain useful extra information, however, the understanding of the transduction principle needs to be improved.