

Not humming, but I do make noise intentionally. I’m a big guy and understand that I could be threatening to women in the wrong circumstance. I also walk fairly quietly just as a matter of the way I walk; so, I’ve scared folks on more than one occasion by “sneaking” up on them unintentionally. So, if I think I am doing that, I’ll land a few footfalls hard and flat to make my foot slap the ground and alert the person of my presence before I get too close. I also try to give space to strangers while walking. Things like moving to the other side of the sidewalk/street, slowing down or speeding up to pass. Basically, trying to not look like I’m stalking them.
Step one: Document, Document, Document.
Step Two: Did we cover documentation yet?
Step Three: Complain, with documentation, to the apartment management.
Step Four: Document.
Recordings such as video and audio are useful. Just keeping a log of all such interactions can help as well. But, you want to have the documentation to prove your side of things. If things go really sideways and you end up in court, the judge won’t give a fuck about what you say, only what you can prove. Be ready to prove your claims. As we say in the DFIR world, “logs or it didn’t happen”. Then, start complaining to management. And document (keep a written log, you probably won’t be able to record) your interactions with management. All logs should include date, time, who you spoke with, what you spoke about and any actions which management said they would take or actions you said you would take. If it’s an option, keep your communications with management in email. Both the sending and received emails will be timestamped and the headers will provide a reasonable record showing that the emails were to or from management controlled email servers and addresses. And they log what was talked about quite nicely.
Ultimately, the goal is to move this from being your problem to management’s problem. And it’s possible that your problem neighbor is also someone else’s problem. If management has three tenants all complaining about the same neighbor, they have more impetus to take action against the problem. Of course, this assumes a neutral management, which can be an open question. But, this is likely the least costly way to resolve the issue.