An acoustical sorting system was developed to detect hollow heart (cavity) of potato tubers (Spun-ta variety). The system includes a microphone and digital signal processing hardware. It was found that upon impact with a steel plate, potato tubers with no hollow heart emit sound with higher signal magnitudes than with hollow one. Linear discrimi-nate analysis was used to classify potato tubers using three features extracted from the micro-phone signal. One of the discriminate features is the integrated absolute value of microphone output signal. The other two features are the number of data points in the digitized microphone signal after impact that have a slope and signal magnitude below preset threshold levels. The classification accuracy of this system is approximately 98%. The internal quality of potato tubers can be detected by acoustic impact method. The resonant frequency of potato tubers after dropping was found from acquired signal. The hollow heart existence of po-tato tubers can be evaluated by the resonant fre-quency of vibration signal of dropping tubers. This technology of acoustics to evaluate the hollow heart existence is more reliable and accurate spe-cially for export.