Headphones
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Headphones From Wikipedia, the free encyclopedia Headphones (or "head-phones" in the early days of telephony and radio) are a pair of small loudspeakers that are designed to be held in place close to a user's ears. They are electroacoustic transducers which convert an electrical signal to a corresponding sound in the user's ear. Headphones are designed to allow a single user to listen to an audio source privately, in contrast to a loudspeaker which emits sound into the open air, allowing anyone nearby to listen. They are also known as earspeakers, earphones [1] or, colloquially, cans. [2] The alternate in-ear versions are known as earbuds or earphones. [1] In the context of telecommunication, a headset is a combination of headphone and microphone. Headphones either have wires for connection to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game consoles, electronic musical instrument, or have a wireless device, which is used to pick up signal without using a cable. Headphones are made in a range of different audio reproduction quality capabilities. Headsets designed for telephone use typically cannot reproduce sound with the high fidelity of expensive units designed for music listening by audiophiles. Headphones that use cables typically have either a 1/4 inch (6.35mm) or 1/8 inch (3.5mm) phone jack for plugging the headphones into the sound source. History 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 in 1910 by Nathaniel Baldwin, who made them by hand in his kitchen and sold them to the United States Navy. [3][4] Some 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, with either single ended or balanced armatures. The requirement for high sensitivity meant that no dampening was used, thus the sound quality was crude. These early models lacked padding, and often produced excessive clamping forces on the wearer's head. Their impedance varied; headphones used in telegraph and telephone work had an impedance of 75 ohms. Those used with early wireless radio had to be more sensitive and were made with more turns of finer wire. Impedance of 1000 to 2000 ohms was common, which suited both crystal sets and triode receivers. In early powered radios, the headphone was part of the vacuum tube's plate circuit and carried dangerous voltages. It was normally connected directly to the positive high voltage battery terminal, and the other battery terminal was securely grounded. The use of bare electrical connections meant that users could be shocked if they touched the bare headphone connections while adjusting an uncomfortable headset. In 1943, John C. Koss, an audiophile and jazz musician from Milwaukee, produced the first stereo headphones. Previously, headphones were used only by telephone and radio operators, and individuals in similar industries. Applications Headphones may be used with stationary CD and DVD players, home theater, personal computers, or portable devices (e.g. digital audio player/mp3 player, mobile phone, etc.). Cordless headphones are not connected to their source by a wire. Instead, they receive a radio or infrared signal encoded using a radio or infrared transmission link, such as FM, Bluetooth or Wi-Fi. These are powered receiver systems, of which the headphone is only a component. Cordless headphones are used with events such as a Silent disco or Silent Gig. Headphones - Wikipedia, th e f ree encyclopedia htt p://en.wikipedia.org/wiki/Headphones 1 of 11 3/6/2015 2:56 PM
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Transcript of Headphones
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HeadphonesFrom Wikipedia, the free encyclopedia
Headphones (or "head-phones" in the early days of telephony and radio) are a pair of small loudspeakersthat are designed to be held in place close to a user's ears. They are electroacoustic transducers whichconvert an electrical signal to a corresponding sound in the user's ear. Headphones are designed to allow a singleuser to listen to an audio source privately, in contrast to a loudspeaker which emits sound into the open air,allowing anyone nearby to listen. They are also known as earspeakers, earphones[1] or, colloquially, cans.[2]The alternate in-ear versions are known as earbuds or earphones.[1] In the context of telecommunication, aheadset is a combination of headphone and microphone. Headphones either have wires for connection to asignal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video gameconsoles, electronic musical instrument, or have a wireless device, which is used to pick up signal without usinga cable.
Headphones are made in a range of different audio reproduction quality capabilities. Headsets designed fortelephone use typically cannot reproduce sound with the high fidelity of expensive units designed for musiclistening by audiophiles. Headphones that use cables typically have either a 1/4 inch (6.35mm) or 1/8 inch(3.5mm) phone jack for plugging the headphones into the sound source.
HistoryHeadphones originated from the earpiece, and were the only way to listen to electrical audio signals beforeamplifiers were developed. The first truly successful set was developed in 1910 by Nathaniel Baldwin, whomade them by hand in his kitchen and sold them to the United States Navy.[3][4]
Some very sensitive headphones, such as those manufactured by Brandes around 1919, were commonly usedfor early radio work. These early headphones used moving iron drivers, with either single ended or balancedarmatures. The requirement for high sensitivity meant that no dampening was used, thus the sound quality wascrude. These early models lacked padding, and often produced excessive clamping forces on the wearer's head.Their impedance varied; headphones used in telegraph and telephone work had an impedance of 75 ohms.Those used with early wireless radio had to be more sensitive and were made with more turns of finer wire.Impedance of 1000 to 2000 ohms was common, which suited both crystal sets and triode receivers.
In early powered radios, the headphone was part of the vacuum tube's plate circuit and carried dangerousvoltages. It was normally connected directly to the positive high voltage battery terminal, and the other batteryterminal was securely grounded. The use of bare electrical connections meant that users could be shocked ifthey touched the bare headphone connections while adjusting an uncomfortable headset.In 1943, John C. Koss, an audiophile and jazz musician from Milwaukee, produced the first stereo headphones.Previously, headphones were used only by telephone and radio operators, and individuals in similar industries.
ApplicationsHeadphones may be used with stationary CD and DVD players, home theater, personal computers, or portabledevices (e.g. digital audio player/mp3 player, mobile phone, etc.). Cordless headphones are not connected totheir source by a wire. Instead, they receive a radio or infrared signal encoded using a radio or infraredtransmission link, such as FM, Bluetooth or Wi-Fi. These are powered receiver systems, of which the headphoneis only a component. Cordless headphones are used with events such as a Silent disco or Silent Gig.
Headphones - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Headphones
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