Headphones have been around for almost a hundred years in various formats and date back to the birth of radio and telephony. Their primary function is to feed sound directly into the ears from a close proximity whilst masking out all other external sound sources. Headphones are in fact small, scaled down loudspeakers fitted into oval shaped ear-cushions that are fitted to the sides of the head by a metallic or plastic frame and in recording studios are referred to as 'cans'.
Earphones by comparison are a relatively new option to headphones and are wedged directly outside the ear canal. Because of this they are relatively inefficient as their lack of isolation forces the user to deploy them at much higher volumes than for example headphones, where outside noise is blocked out by the foam surround of the sealed headphone. Earphones are typically used with iPods and MP3 players along with a further option known as "Ear-buds" which are tiny speakers that are inserted directly inside the ear canal.
