An operation method of a terminal may include: executing a voice call service between the terminal and at least one terminal; determining at least one short-range terminal existing within a preset range from among the at least one terminal, based on location information of the terminal; detecting a howling frequency band in which howling occurs between the terminal and the at least one short-range terminal from among a plurality of frequency bands in which the voice call service is performed, based on information of the plurality of frequency bands; and removing the howling by adjusting a gain of the howling frequency band.