An audio system and method of extracting indoor reflection characteristics, the method including generating a detection signal based on an input signal and a modulation code, outputting a sound signal generated based on the detection signal through a plurality of speakers, measuring sound signals output through the plurality of speakers, or sound signals reflected by a wall of a space in which the plurality of speakers is installed, and extracting reflection characteristics of the space based on the measured sound signals and the modulation code, is disclosed.