A strange sound called 'the hum' might be driving people crazy

Listen.

All around you are sounds, right? You might be reading this on a laptop with a whirring fan, or on your phone on a rattling subway, or even at home, with music or the air-conditioner on, adding a thin layer of white noise to everything you hear.

Now take all that away. What's left?

For about 2% of people, it's "the hum."

READ MORE:http://www.businessinsider.com/the-bristol-hum-mystery-crazy-people-2016-4