[makoto12]

You want to start with narrow band. So object tracking, where the object is emitting a single frequency is a great start.

i think at 2khz (it is blazingly irritating to listen to), you need to space your microphones about 15cm apart. so you don't need too much room. Then it's just hooking up 4-6 microphones to a wooden board. Sampling with a decent microprocessor. You can do the processing on board, or ship it to a laptop, and do the processing there.

Just take care with your microphones and sampling. Any large defects will greatly inhibit your results.

Then for the algorithm, do a delay and sum. it's the dumbest approach, but the easiest to understand, and should work