A three-microphone system for real-time directional analysis: toward a device for environmental monitoring in...

Sound localization is a problem for the hearing impaired, deaf, and deaf-blind. A laboratory prototype of a three-microphone digital system for real-time directional analysis of sound sources that is mounted on eyeglasses has been developed. A cross-correlation algorithm is used for determinations of time and phase differences between the three microphone signals. The equipment was evaluated in a sound-treated test room with noise and speech stimuli from 12 different directions. It has an adequate precision (within approximately +/- 10 degrees) for speech and noise bursts in the frequency range 0.5-4 kHz, and for testing with words in a sound field the error percentage is very close to 0 at 0-degrees azimuth. The robustness of the algorithm in terms of signal-to-noise ratio is documented and reaches about +8 dB in different directions for speech and up to 0 dB for noise bursts. It is concluded that the construction of a robust system for directional analysis with sufficient efficiency for further experiments has been achieved.