Not all schizophrenics hear voices that seem to be coming from the tv, computer, pictures, other people, etc. They can just be hearing external voices that don't seem to be coming from any particular sorce...they may seem to simply be coming from the air around them.

...i'm only trying to help educate you, because like you said you only just started researching it and that your son may have it . Schizophrenia is very complicated. I believe i know a lot about the disease. I myself at first didn't believe i was hearing voices because i thought to be termed "hearing voices" they had to be external...but as i learned more about the illness and talked to more and more schizophrenics, i realized i was wrong.