Enhanced Directional Sensitivity using Acoustic Dish Reflector

An acoustic reflector is a passive device which is used with microphones to reflect and focus sound waves from a longer distance. They are effective for long-range sound recording without intrusion, such as to record wildlife sounds. In this paper, our objective is to investigate the feasibility of using a dish reflector microphone for indoor activity monitoring of large premises. Acoustic gain and frequency response of the microphone with different parabolic, near parabolic and non-parabolic reflectors are compared with that of the same microphone without the reflector. It is observed that the use of dish reflector does significantly enhance the directivity and sensitivity of sound recording. Keeping to a moderate size reflector, among various shapes and materials, the best reflector has given a 14 dB gain improvement over microphone without reflector at 0 degree azimuth. We also found that among steel and plastic dish reflector of approximately same size and shape, steel dish reflector does give a higher performance as expected. The increased directivity of the dish reflector is giving a significant improvement in indoor monitoring and also for sound source tracking.