Synchronized phenomena have been observed in various areas, such as mechanical, electrical and chemical engineering. Mutual interaction plays an important role in synchronized phenomena. In this study, we explore the possibility of quenching self-excited sounds generated from two Helmholtz resonators by mutual interaction. Two resonators are connected with tube at the bottom of each resonator. To quench a self-excited sound using another self-excited sound as interference, the frequencies of the two sounds must be identical and their phases opposite. Accordingly, in this study synchronization is performed to match the frequencies and maintain the phases. To induce synchronization, a certain type of interaction must be utilized; thus, an acoustic interaction is used. We sought in-phase and antiphase conditions experimentally and found that the phase of self-excited sounds depends on the length of the tube connecting the two resonators.