I record EVPs and I have come across some scary voices, and even spirits that were intentionally trying to scare me, but none have turned out to be demons.

In my opinion, if recording EVPs scare you enough that it disturbs your sleep, than you shouldn't be recording. Recording just encourages more contact, and fear is a very negative energy. Negativity attracts negativity. . .not demons, just spirits that may like to have some devious fun at your expense.