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Headphones are a pair of small loudspeakers, or less at a single speaker with their ears close to the way users and links such as audio amplifier, radio or CD player into a source method. They are also known as stereophones, headsets or, colloquially cans. The in-ear versions are known as earphones. In the telecommunications, the term headset is used to describe a pair of headphones and microphone combination of two way communication, such as telephone.
The telephone earpiece beginning of the 20th century. Headphones developed from the earpiece. Before amplifiers were developed, sensitive headphones were the only way to listen to audio signals. Brandes manufactured very sensitive headphone around 1919 which were usually used for early radio work.These early headphones used moving iron drivers, single ended, or balanced armature. Because there is no damping was used, the sound quality was crude. Besides that, they had very poor comfort compared to modern types. They usually have no padding and too excessive clamping force to the head. Their impedance varied, headphones which work in telegraph and telephone had an impedance of 75 ohms. Those who used with early wireless radio had to be more sensitive and were made with more turns of finer wire. Impedance of 1,000 to 2,000 ohms was common, which suited for both crystal sets and triode receivers.In early powered radios, the headphone was part of the vacuum tube's plate circuit which had dangerous voltages on it. It was normally connected directly to the positive high voltage battery terminal while the other battery terminal was securely earthed. Users will be shocked if they touched the bare headphone connections while adjusting an uncomfortable headset.
Application of headphones
Headphones can be used with fixed equipment such as CD or DVD players, home theater, personal computers and portable devices.Cordless/ wireless headphones are not connected by a wire. It receives from a radio or infrared signals encoded using a radio or infrared transmission link such as FM, Bluetooth or Wi-Fi.In the professional audio sector, headphones are used in live situations.In radio studios, DJs use headphones to get rid of acoustic feedback and monitor their own voice.In studio recordings, musicians and singers use headphones to play along to a backing track. In the military, audio signals of many varieties are monitored using headphones.
Types of headphones
Generally, headphones can be divided into four separate categories. They are circumaural, supra-aural, earbud, and in-ear.
Circumaural/full size headphones have large pads that surround the outer ear so that they can against the head to attenuate any intrusive external noise. They can be heavy and there are some sets which weigh over 500 grams.
Supra-aural headphones have pads that sit on top of the ears, rather than around them. They tend to be smaller and more lightweight than circumaural headphones. Therefore, they are resulting in less attenuation of outside noise.
Earbuds/ earphones are much smaller and inserted directly outside the ear canel, but not completely surrounded. They generally inexpensive, portability,and convenience. Earbuds inability to provide any isolation. In order to drown out noise from the user's surroundings, they often used at higher volumes which can increases the risk of hearing-loss.
In-ear are earphones that are inserted directly into the ear canal. In-ear offer portability similar to earbuds, and also act as earplugs to provide isolation from outside noise.
Headphone transducers use one or more of several methods of sound reproduction.
The moving coil/ dynamic driver is the most common type used in headphones.The stationary magnet affixed to the supporting frame of the headphone to create a static magnetic field. The main elements of this type of magnet are neodymium or ferrite composite.The diaphragm of the headphone is affixed to the voice coil.A common type of moving-coil headphone drivers are based on the microphone capsule technology.
An electret transducer functions by carrying a permanent built-in charge. They are not a very common design type and neither are their close relative, the electrostatic transducer. In addition they are cheaper and cannot reproduce the same fidelity as electrostatics.
The drivers in an electrostatic transducer are comprised of a very thin charged electrical diaphragm. It is common for a PET film membrane to be placed between two perforated metal plates.The sound signal creates an electrical field. Air is then forced through the perforations and then is merged with an ever-changing electrical signal that drives the membrane. This process causes a sound wave to be produced.Due to the electrostatic headphones wider frequency range, they are usually more dear than their moving-coil counterparts and the quality of the components used in the manufacturing process.
Benefits and limitations
Headphones may be used to prevent other people from hearing the sound for privacy or to prevent disturbance, as in listening in a public library.Headphones are also useful for video games that use 3D positional audio processing algorithms because they allow players to better judge the position of an off-screen sound source Although modern headphones have been particularly widely sold and used for listening to stereo recordings since the release of the Walkman, there is subjective debate regarding the nature of their reproduction of stereo sound. Stereo recordings represent the position of horizontal depth cues via volume differences of the sound in question between the two channels. When the sounds from two speakers mix, they create the phase difference the brain uses to locate direction.Through most of the headphones, the right and left channels do not combine in this manner, the illusion of the phantom center can be perceived as lost. Hard panned sounds will also only be heard only in one ear rather than from one side. This latter point is of particular importance for earlier stereo recordings which were less sophisticated, sometimes playing vocals through one channel and music through the other.Headsets can have ergonomic benefits over traditional telephone handsets. They allow call center agents to maintain better posture instead of tilting their head sideways to cradle a handset.The common scenario in which a replacement might need to be purchased is the physical breakdown of copper wiring at junction points on the cord These are the sites of greatest and most stressful motion on a cord and so they are typically fitted with some kind of strain relief.
Dangers and volume solutions
Using headphones at a very high volume level may cause temporary hearing impairment or deafness due to an effect called "masking." The headphone volume has to compete with the background noise, especially in excessively loud places such as subway stations, aircraft, and large crowds because it will lead to the disappearance of the normal pain connected with the higher levels of volumes. Excessively loud volume may be damaging if extended period time of using it, however, one hearing expert bring about that "fewer than 5% of users select volume levels and listen frequently enough to risk hearing loss."Most of the manufacturers of portable music devices have try to introduce safety circuitry to users.They have attempted to limit the output volume and have warned the users that there have a certain dangerous way when the volume was being used is too high. Unfortunately, the concept has been rejected by most of the buyers who favors the personal choice of high volume. The government of France has placed a limit on all music players sold in the country. That is they must not be capable of producing more than 100dBA which will cause hearing impairment. Canalphones and in-ear monitors are being less likely to cause hearing impairment in noisy environments because much of the external noise is physically blocked out due to the noise isolation properties of the in-ear seal. This allows the user to listen at lower volume levels. Exercising while listening to music through headphones can be dangerous.It is because blood may be diverted from the ears, limbs, left more vulnerable to damage the inner ear. A study group has recommended that exercisers should set their headphone volumes to half of their normal loudness and only use them for a half hour.
The very first headphones were consist of handmade materials that were readily available such as rubber, leather, copper, and ceramics. Headphones in more modern times still are made based on the same principles but highly advanced. Headphones are now amount produced and made with a wide spectrum of different materials including vinyl, foam, silicone, advanced plastics, artificial leather, textiles and more.Nathaniel Baldwin invented headphones in 1910, they have undergone a radical evolution in style, design and performance.Early headphones were largely handmade and constructed from materials common to electrical products of the era---mainly copper, rubber, leather and technical ceramics. Modern headphones are generally highly engineered, mass-produced and made with sophisticated plastics, silicone, artificial leather, rubber, textiles, vinyl and foam materials.
Top ten headphones and earphones
BoseÂ® QuietComfortÂ® 3 Acoustic Noise CancellingÂ® Headphones
* On-ear fit: Earcups rest gently on your ears
* Bose noise reduction and quality sound for travel, work and home
* Comfortable, lightweight design with an on-ear fit: headphones rest gently on your ears
* Rechargeable lithium-ion battery: 25 hours average use per charge
* Fold-flat earcups for easy storage in slim carrying case
2. Shure SE530 Sound Isolating Earphones
* Triple speakers for sound that rivals live performance
* Triple TruAcoustic MicroSpeakers: Dedicated Tweeter and Dual Woofers
* Sound Isolation Technology reduces background noise better than noise-cancelling headphones, without batteries or added hiss
* Premium Fit Kit including a selection of interchangeable sleeves for personalized, comfortable fit; 3â€² extension cable; 9â€³ cable; premium carrying case; volume control; Â¼" adapter; airline adapter
* Modular Cable Design lets users choose different cable lengths to suit different music player locations (armband, pocket etc.)
3. Westone 3 New 3-way Driver
* New 3 Way Driver, compared to the Triple Driver
* Soft padded travel case, ten different eartips, and wax loop for cleaning.
* Sensitivity: 107 dB SPL
* Frequency response: 20 Hz -18 kHz
* Impedance: 30 ohms
* Driver: Balanced armature
* Features: Soft padded travel case, ten different eartips, and wax loop for cleaning.
* Standard Color: Black There is a difference between the 3-way driver and the triple driver. The Triple Driver is a Dual Bass Driver and one High Driver.
4. Sennheiser HD650 Audiophile Open Dynamic Stereo Headphone
* Specially designed acoustic silk ensures precision damping over the entire frequency range and helps to reduce THD to an incredible 0.05%
* Improved frequency response is 10 - 39,500 Hz (-10 dB)
* Hand-selected matched driver elements
* High power neodymium magnets deliver maximum efficiency
* Lightweight aluminum voice coils for very fast transient response
* Price: $430
5. Audio-Technica ATH-ANC7 QuietPoint Active Noise-Cancelling Headphones
* ATH-ANC7 QuietPoint active noise-cancelling headphones effectively reduces environmental noise by up to 85% with or without audio
* Ideal for travel and use with MP3, CD, DVD and in-flight entertainment systems
* Provides superior audio quality with 40mm drivers with neodymium magnet systems in each earpiece for deeper bass, extended treble and higher fidelity
* Fully integrated active noise-cancelling technology - no external modules needed
* Includes a detachable cable (remove for noise-cancelling function without audio) with 3.5 mm mini-plugs, a full-size Â¼" adapter, a specialized airline adapter for connecting to in-flight entertainment systems, and a handy carrying case
6. Ultimate Ears Super.Fi 5 Noise Isolating Earphones
* Noise isolating design and customizable ear tips maximize noise isolation from the environment and allows the listener to listen at lower volumes
* Innovative top fire armature speaker produces powerful and extended high definition sound
* Ultra low profile and lightweight for comfort and fit. Color coded housing for easy left and right identification
* Universal fit kit including silicone ear tips Comply foam ear tips and cleaning tool
* Pebble shaped pocket ready carrying case
7. Shure SCL5 Earphones
* Earphones with Dual Low MassHigh Energy Drivers with In-Line Crossover - Clear.
* Frequency Range 20Hz 18.5kHz.
* Sensitivity 122dB SPLmW.
* Impedance 110 Ohms.
* Input Connector 3.5mm 1/8 inch.
8. Sennheiser MX W1 Wireless Earbud
* wireless headphones for use with Kleer-enabled audio/video devices and any device with a 1/8â€³ headphone jack
* Kleer wireless technology delivers uncompressed stereo transmission over 2.4 GHz wireless frequency range
* "twist-to-fit" earbuds rest just outside the ear canal
* Listen In technology enables two or more people to listen to the same audio stream
* compact transmitter plugs into any mini headphone jack and attaches to your portable device using supplied elastic bands
9. BoseÂ® In-Ear Headphones
* High quality, earbud-style headphones with soft silicone tips that rest gently in your ears
* Proprietary Bose technology produces a full range of sound, including lower notes, in a compact in-ear design
* Color-coded tips in three sizes for a more personal, comfortable fit
* Angled plug fits directly into most MP3 players, including iPod and iPhone models, as well as laptops and portable CD and DVD players
10. Sony Mdr-Ed12Lp/Slv Budstyle Headphones
* Large 16mm drivers for sound quality
* Neodynmium magnets for powerful sound reproduction
* Bass booster
* Convenient cord slider helps eliminate cord tangle