Relax, I believe you!!

Let me tell you what happened to me the other night. I sleep with the fan running and when I was laying on my left side, I could her faint conversations, like a TV down low. I got up and searched, Nope, nobody but me here. Thinking I was partly dreaming, I lay back down, same position and low and behold---the voices again. It sounded like an honest to goodness conversation, one male and one female. When I turn my head, it goes.

It was something about laying in that position that produced those "voices." I can't explain it either.

Now, about hearing the sounds when you shouldnt':

While living with my parents I could hear their pendulum clock go off at the hour, and it made a god-awful noise, like a sick bird with a loose voice box.

For some strange reason, I kept hearing it afterward, over and over again, I thought I was going insane. I had to lay there calmly and tell myself that I wasnt' going crazy, it was just an echo residue from that awful noise.

I was able after awhile to drift off to sleep.

I do think sounds echo in your head when you don't want them to. Obviously from the tone of your post, the voices from the ventilator disturb you and they are "haunting" you when it's quiet.

Try to relax and listen to some soft music in its place.