The invention discloses a method and a device for adjusting an
audio frequency and a sound apparatus. The method comprises the following steps of outwards projecting
infrared light spots through a speckle projecting device; receiving reflected light rays, reflected back by the
infrared light spots, through an
infrared receiving device; determining the distribution information of surrounding obstacles according to the reflected light rays; adjusting the output characteristic of the
audio frequency according to the distribution information of the obstacles. The method for adjusting the
audio frequency, which is provided by an embodiment of the invention, by utilizing the speckle projecting device and the infrared receiving device, and by adopting the way that infrared rays are used as activebeacons to perceive an environment, is used for realizing the
active detection and the self-
adaptation adjustment on the environment. In comparison with existing detection ways of an ultrasonic wave,and the like, the realization cost of infrared detection is lower; moreover, the infrared detection is friendly to a surrounding environment; the undesirable influence cannot be generated to the surrounding environment (such as a pet, and the like), and the user experience is promoted.