Completely AZ: Little Help?

[Suicide Junkie]

Ear plugs should help you decide if it is a real sound coming from the house or not.
Tinnitus is annoying.

[Caduceus]

I agree with RD and SJ. Of course it could be a side-effect or tinnitus (ear ringing). The best idea would be to sit in a room you've heard it before with another person, being completely quiet and seeing if you both hear it. If you do and they don't, I start looking at the medications or another symptom of the schizophrenia.