Electronic apparatus and power controlling method thereof

A sound output apparatus comprising:

• an input unit including input circuitry;
• an output unit including output circuitry;
• and
• a processor configured to:
• perform first-filtering of a frequency band of an audio signal received through the input unit via a filter, wherein the filter for the first-filtering is selected from a plurality of stored filters based on a sound pressure of the sound output apparatus that is determined obtained based on volume information of the sound output apparatus,
• perform second-filtering of a frequency band of the first-filtered audio signal via another filter, the another filter for the second-filtering being based on a frequency response characteristic of the sound output apparatus,
• adjust a loudness of the received audio signal based on a perception volume level of the second-filtered audio signal, and
• output the adjusted audio signal through the output unit.