Directional hearing

Sound localization refers to a listener's ability to identify the location or origin of a detected sound in direction and distance. The sound localization technique appeared with the considerable progress that has been made in acoustic simulation techniques. It allows us to localize the acoustic sources by modeling a sound field that contains one or several sources. Therefore, with such technique, people can obtain the hearing sense from any place in the sound field. It may also refer to the methods in acoustical engineering to simulate the placement of an auditory cue in a virtual 3D space (see binaural recording, wave field synthesis).

The sound localization mechanisms of the mammalian auditory system have been extensively studied. As a new intersect discipline, sound localization involves psychological acoustics, physiological acoustics, artificial intelligence and high performance computing (HPC) system. It has been widely applied on transmitting data, information recognition and improving the immersion feelings, the fidelity and the feeling of reality of 3D environment, which can be implemented both in military and civilian areas.

The auditory system uses several cues for sound source localization, including time- and level-differences (or intensity-difference) between both ears, spectral information, timing analysis, correlation analysis, and pattern matching. These cues are also used by other animals, but there may be differences in usage, and there are also localization cues which are absent in the human auditory system, such as the effects of ear movements. Animals with the ability to localize sound have a clear evolutionary advantage.

Sound is the perceptual result of mechanical vibrations traveling through a medium such as air or water. Through the mechanisms of compression and rarefaction, sound waves travel through the air, bounce off the pinna and concha of the exterior ear, and enter the ear canal. The sound waves vibrate the tympanic membrane (ear drum), causing the three bones of the middle ear to vibrate, which then sends the energy through the oval window and into the cochlea where it is changed into a chemical signal by hair cells in the organ of corti, which synapse onto spiral ganglion fibers that travel through the cochlear nerve into the brain.

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