Sound: It's in your head

(Aug 29, 2019) Most of the sounds in our environment are filtered out by the brain. And what we do hear can be altered in pitch and character by simply shaping the space around the ear with a hand or with a seashell. The volume and range of sounds we perceive can change dramatically, depending on whether the preceding environment was loud or quiet. And the brain is capable of generating sound where there is none.