Why do our ears ring?

Inside the cochlea, thousands of delicate hair cells convert sound vibrations into electrical signals for the brain. Loud noise from concerts, headphones or machinery can bend or damage these cells, and the auditory system responds by increasing its own internal activity. The brain interprets this extra activity as a ringing, buzzing or hissing sound that has no outside source. Temporary ringing after a loud event usually fades within hours or days, but repeated exposure can cause permanent tinnitus. Ageing, earwax blockages, ear infections and some medicines can also trigger it, and it is estimated to affect roughly 10 to 15 percent of adults.