I often experience this:
There will be a background noise (a refrigerator compressor, or a computer fan, or water pipes in the wall, etc) which is steady and ongoing for some time (many minutes, or hours), I am only vaguely aware of the noise for most of this time, but then the noise suddenly comes to my conscious attention...
...two seconds before the noise stops.
I guess I'm picking up on a subtle shift in the sound as the machinery driving it begins its halt procedure. Seems reasonable, but I find the experience very eerie because whatever I'm picking up on is too subtle for me to be aware of it. Rather, I am aware only of my sudden increase in awareness, without knowing why that awareness should heighten until, about 2 seconds later, the noise stops.
Is there a name for this phenomenon?
This only seems to happen with sound for me, not other senses. (I won't become aware of the sight of a dog just before it sits up, for example.) Is there a particular reason why auditory processing should have this effect?