Headphones are a pair of small loudspeakers which are designed to be held in place close to a user's ears. Headphones have wires which allow them to be connected to a signal source such as an audio amplifier, radio, CD player, or portable media player. They are also known as stereophones or, colloquially, cans. The in-ear versions are known as earphones or earbuds. In the context of telecommunication, the term headset is used to describe a combination of headphone and microphone. Headphones originated from the earpiece, and were the only way to listen to electrical audio signals before amplifiers were developed. The first truly successful set was developed by Nathaniel Baldwin, who made them by hand in his kitchen and sold them to the United States Navy. Very sensitive headphones such as those manufactured by Brandes around 1919 were commonly used for early radio work. These early headphones used moving iron drivers, either single ended or balanced armature.
Contributions by Raul.saavedra, Lindosland, and Mark Kim.