Headphones are a pair of small
loudspeakers, or less commonly a single speaker, with a way of holding them close to a user's
ears and a means of connecting them to a signal source such as an audio
amplifier,
radio or
CD player. They are also known as
stereophones,
headsets 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 used for
two-way communication, for example with a
telephone.
- Types of headphones
The particular needs of the listener determine the choice of headphone. The need for portability indicates smaller, lighter headphones but can mean a compromise in fidelity. Headphones used as part of a home hi-fi do not have the same design constraints and can be larger and heavier. Generally, headphone form factors can be divided into four separate categories:
circumaural,
supra-aural,
earbud, and
in-ear.
Circumaural headphones have large pads that surround the outer ear.
(sometimes called
full size headphones) have circular or ellipsoid earpads that encompass the ears. Because these headphones completely surround the ear, circumaural headphones can be designed to fully seal against the head to attenuate any intrusive external noise. Because of their size, circumaural headphones can be heavy and there are some sets which weigh over 500 grams (1 lb). Good headband and earpad design is required to reduce discomfort resulting from weight.
A pair of supra-aural headphones.
have pads that sit on top of the ears, rather than around them. They were commonly bundled with
personal stereos during the 1980s. This type of headphone generally tends to be smaller and more lightweight than circumaural headphones, resulting in less attenuation of outside noise.
Earbuds or
earphones are headphones of a much smaller size that are placed directly outside of the ear canal, but without fully enveloping it. They are generally inexpensive and are favored for their portability and convenience. Due to their inability to provide any isolation they are often used at higher volumes in order to drown out noise from the user's surroundings, which increases the risk of
hearing-loss.
[3] During the 1990s and 2000s, earbuds became a common type bundled with personal music devices.
Main article:
In-ear monitor
In-ear monitors extend into the ear canal, providing isolation from outside noise.
(also known as
IEMs or
canalphones) are earphones that are inserted directly into the ear canal. Canalphones offer portability similar to earbuds, and also act as earplugs to block out environmental noise. There are two main types of IEMs: universal and custom. Universal canalphones provide one or more stock sleeve size(s) to fit various ear canals, which are commonly made out of
silicone rubber,
elastomer, or foam, for noise isolation. Custom canalphones are fitted to the ears of each individual. Castings of the ear canals are made and the manufacturer uses the castings to create custom-molded silicone rubber or elastomer plugs that provide added comfort and noise isolation. Because of the individualized labor involved, custom IEMs are more expensive than universal IEMs and resell value is very low as they are unlikely to fit other people.
A headset is a headphone combined with a
microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. The most common uses for headsets are in console or PC gaming,
Call centres and other telephone-intensive jobs and also for personal use at the computer to facilitate comfortable simultaneous conversation and typing. Headsets are made with either a single-earpiece (mono) or a double-earpiece (mono to both ears or stereo). The microphone arm of headsets is either an external microphone type where the microphone is held in front of the user's mouth, or a voicetube type where the microphone is housed in the earpiece and speech reaches it by means of a hollow tube.
Telephone headsets connect to a
fixed-line telephone system. A telephone headset functions by replacing the
handset of a telephone. All telephone headsets come in a standard
4P4C commonly called an RJ-9 connector.
For older models of telephones, the headset microphone
impedance is different from that of the original handset, requiring a telephone amplifier for the telephone headset. A telephone amplifier provides basic pin-alignment similar to a telephone headset adaptor, but it also offers sound
amplification for the microphone as well as the loudspeakers. Most models of telephone amplifiers offer volume control for loudspeaker as well as microphone, mute function and headset/handset switching. Telephone amplifiers are powered by batteries or
AC adaptors
