During my senior year at Northeastern, I created a microphone array listening system for hearing-impaired professors with my Capstone team. Our final design included a nested array placed in the front of the classroom, that honed in on a given direction via a spotlight system, as visualized below:

Our array worked to specifically enhance important frequencies in the human speech signal, and amplify students at a long range (a particular difficulty of modern hearing aids). Below is the basic signal flow diagram for our array system:

Here is a download of our final presentation, which includes many more specifics of our projects, most notably some of our more advanced Matlab simulations.