I get this, too! I never really thought about what it might be, I always kind of just assumed it was that I normally meditate when the house is quiet and so I hear these things better, but now that I come to think of it, perhaps the raised and/or manipulated energy is having some effect on the surroundings? Interesting...

I do know that prior to warding the house and property and my person, when I would meditate or do any other thing that raised or manipulated energy (some kinds of prayer, for example, will do it), I would draw the attention of various astral entities, something like moths to a flame (if moths were parasites, that is).