Earphones

Listing ID #4409700

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.

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 (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). Ergonomic headband and earpad design is required to reduce discomfort resulting from weight.

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 lighter than circumaural headphones, resulting in less attenuation of outside noise.

Circumaural and supra-aural headphones can both also be further differentiated by the type of earcups:

Open-back headphones have the back of the earcups open. This leaks more sound out of the headphone and also lets more ambient sounds into the headphone, but gives a more natural or speaker-like sound and more spacious "soundscape" - the perception of distance from the source.

Closed-back (or sealed) styles have the back of the earcups closed. Depending on the model they may block 8-32db of ambient noise, but have a smaller soundscape, giving the wearer a perception that the sound is coming from within their head., one reason for this is that there are sounds reflected back towards the ear.

In-ear headphones, like earbuds, are small and without headband, but are inserted in the ear canal itself. They are sometimes known as canalphones. Price and quality range from relatively inexpensive to very high; the better ones are called in-ear monitors (IEMs) and are used by audio engineers and musicians as well as audiophiles.

Canalphones offer portability similar to earbuds, block out much environmental noise by obstructing the ear canals, and are far less prone to falling out. When used for casual portable use they block out sounds which can be important for safety (e.g., approaching vehicles).

• Universal canalphones provide one or more stock silicone rubber, elastomer, or foam sleeves to fit various ear canals, for correct placement and best noise isolation.
• Custom canalphones are fitted to the ears of the individual user: 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; resale value is very low as they are unlikely to fit other people.

Telephone headsets connect to a fixed-line telephone system. A telephone headset functions by replacing the handset of a telephone. Headsets for standard corded telephones are fitted with a standard 4P4C commonly called an RJ-9 connector. Headsets are also available with 2.5mm jack sockets for many DECT phones and other applications. Cordless bluetooth headsets are available, and often used with mobile telephones. Headsets are widely used for telephone-intensive jobs, in particular by call centre workers. They are also used by anyone wishing to hold telephone conversations with both hands free.

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 switching between headset and handset. Telephone amplifiers are powered by batteries or AC adaptors.