Acoustic Beamforming Array Using Feedback-Controlled Microphones for Tuning and Self-Matching of Frequency Response

NASA's Langley Research Center, in collaboration with Michigan State University (MSU), has developed a microphone array that identifies the locations and strengths of acoustic sources using sensors that are “self-calibrated” with closed-loop feedback control. This results in an array that can be considered “self-matching.” Beamforming microphone arrays typically consist of tens to hundreds of microphones. The location of an acoustic source can be determined by exploiting the acoustic wave propagation delays from the source to each of the microphones. For the system to be accurate, each microphone must be calibrated to account for varying magnitude and phase frequency responses. Manual calibration is time-consuming and may need to be repeated regularly to take into account effects such as heat and humidity. The NASA Langley/MSU innovation removes such time-consuming calibration and provides more accurate results.