Headphones are headphones designed to be worn on or around the head over a user’s ears. Headphones can also include in-ear monitors and earbuds. They were first designed for use with telephone exchange systems, public address systems, and the radio. The audio signal from a compact disc player is fed into one earpiece so that the user can listen to both ears simultaneously.

It can be done by either splitting the signal or using headphones with two separate drivers. A headphone has an on-off switch between each earpiece so that they are disconnected. To hear external sounds while listening to music on headphones, an adjustable swivel spool is used as a microphone that converts the vibrations of sound waves into electrical signals that are then amplified and reproduced by loudspeakers inside the headphone cups.

Types of Headphones

1. Open-Back Headphones. The open-back design has a larger and more spacious sound chamber so that the headphone can deliver higher quality sounds to the user. They often have an over-ear design. A standard design used in bass-heavy headphones is the circumaural due to their size and sound characteristics. It refers to headphones covering the entire ear, enclosing it like a sock or glove.
2. On-Ear Headphones. Generally, an on-ear headphone does not cover both ears. It may cover only the sides of the head or even the back of the head. On-ear headphones are generally portable and used in music listening and gaming consoles with either a detachable or integrated cable for added ease of use and portability.
3. In-Ear Headphones. In-ear headphones are small in size and have a sound chamber that fits inside the ear canal of the user. The in-ear design is much smaller than other types of headphones. In-ear headphones are typically used with a portable music player, such as an MP3 player, iPod, or device.
4. Earbuds. Earbuds are tiny, generally not covering the ears. Earbuds are considered semi-open because their sound chambers are only partially covered by the yoke, connecting the earbuds to an earphone cord.
5. Noise Cancelling Headphones. Noise-canceling headphones are designed to isolate the user from outside noise. Headphones with active noise cancellation use a microphone to pick up outside noises, which are then fed into an electronic circuit to generate opposite sound waves that neutralize the sounds of the external environment. Passive noise-canceling headphones do not have this feature but instead cancel noise by blocking it with an impact-resistant outer shell and heavy padding on the ear cups.

There are many types of headphones available, and they are usually categorized by the materials used to manufacture the headphone. The three most common materials are metal, plastic, and rubber. Some headphones may use any combination of these materials for various reasons.