Noise can travel far in apartment buildings and in non-straight lines... If you are worried and trust that the neighbor comes in good faith, you can ask them t

Noise can travel far in apartment buildings and in non-straight lines... If you are worried and trust that the neighbor comes in good faith, you can ask them to call you once they hear those banging, or even better knock on you door and come in to listen. Recording might not actually help you, as you might record noises and not be able to prove where it comes from. The same applies for renting an acoustic sniper localization system- it might direct you somewhere but not really help find the source