Apologies for posting here at recording.org. I'm a filmmaker and I figured you all would be able to answer my question better than anyone else.

I live in an apartment, and when the central air/heat kicks on, the sound is alarmingly loud. It's actually starting to wake me up in the middle of the night. It's not a problem specific to my apartment unit. I lived here in the past in another unit, same problem.

Mr. Obvious: is there anyway I can mitigate the loudness somehow without blocking the airflow? It's one single supply air vent that is around 4'x2'. I'm imagining some kind of spongy foam or something up around the ceiling along the 3 walls that closely surround it (I know sound waves must be hitting floor, but can't think of anything to do about that. When you enter door of apt. it's directly above you in a hallway.