I recently started to hear fireworks and an audience speak whenever i get somewhat tired. I got into a pretty rough car accident about 2 years ago. I got a terrible concussion and had vertigo for about 5 months. Worst time of my life. Recently i have found that when i lay down and think to myself, i can somewhat hear something in the distance. I don’t believe it’s there, but i will “imagine” it there. It sounds as though it’s outside my house and i can hear the echo of it. I haven’t freaked out over it, but i definitely have noticed it