I believe actual tinnitus is when you hear the ringing involuntarily and in spite of other sounds. When it's quiet and you hear it, it could be several things. Could be you can't hear "nothing" so you have a noise to focus on. Could be something going on in your inner ear that actually makes a ringing noise. I've heard (hehe) that sometimes the noise is real and it can be heard by others.

I've had tinnitis for years also. But it's not really bothersome. I've learned to deal with it mostly. I hardly notice it most of the time.