Yeah I get the ringing in the ears a bunch too. Its like I'll be hearing all the background noises (a/c systems, fridges, etc.) and then its like a switch is turned on and the background noises are replaced with a sound much like that of the familiar turning on night vision sound. Do I make sense?

I can still hear normal conversation and stuff but this phenomenon always throws me and make me try to clear my ears or shake it out....