I think one could build quite the good system with 2 directional microphones and then do some beamforming or how it is called to isolate the depth one want to p

I think one could build quite the good system with 2 directional microphones and then do some beamforming or how it is called to isolate the depth one want to perceive. But this is super expensive since you need calibrated mics etc. The biggest advantage of neural nets in this field is that you can use a dirt cheap microphone and postprocess it so good that it is good enough or even very good for humans.