Update 1/22/25 11:23am: The New York State Office of General Services, which operates the Empire State Plaza, says the noise is related to a heating/cooling issue -  they are working diligently to fix it: 

As OGS works to repair a ruptured supply line that carries water used to regulate the heating and cooling of the Empire State Plaza, temporary equipment has been placed on the Plaza behind the Legislative Office Building and in West Capitol Park to maintain temperate conditions in affected workspaces.

A very consistent, loud noise has reportedly been emanating from the Empire State Plaza. In a post on Reddit, a resident who lives nearby recorded the sound, which is eerily similar to when someone lays on the car horn - but doesn't let up.

Hey all. So for the last two weeks or so there has been an obnoxious sound emanating from the Empire State Plaza toward the State Street end. It sounds like a Buick's horn sounding non-stop in a key of middle D. Seriously, it hasn't ended in all this time, it just keeps going. It's weirdly loud, so I'm surprised I haven't heard anything about this yet, and I'm also surprised the city hasn't shut it down because it's super annoying. I can hear it through my living room window when I'm sitting on the couch watching TV. Has anyone else heard this and/or knows what it is? 

Here's what it sounds like. You'll probably agree it's quite aggravating:

 Some people in the comments say its likely an HVAC issue or maybe something to do with the generators on site. Any ideas?