Headphones are a device used to listen specifically to sound. In the first period of the appearance of the radio, people relied on headphones for listening, and at that time they were in mono format (i.e. with one sound channel) (both headphones emit the same sound because they are connected to the same source of sound). In stereo) Modern types of headphones can display surround sound, as they give the true sense of the direction of the sound source, but they need special equipment and audio material that contains surround sound tracks.
The higher the frequency capacity that the headphone supports, the higher its price and the higher the ability to display sound. Currently, most headphones have a microphone (it may be connected to it through a stick or inside a wire).
Most nuts and bolts support headphones with an impedance of 30 ohms to 40 ohms. The higher the speaker impedance, the lower the sound level it produces, and for this reason we see that large speakers have a low resistance of about 8 ohms.
Date
Headphones arose from the need to free one's hand when operating the phone. There were many products that preceded the "hands-free" headphones. By the 1890s, the first headphone was manufactured by a British company called Electrophone, which had created a system that allowed its customers to communicate directly during performances in theaters and opera houses across London. Subscribers to the service can listen to the performance through a pair of oversized earphones attached under the chin, attached to a long rod.
French engineer Ernest Mercadier patented a set of earphones in 1891.
In 1910, Nathaniel Baldwin of Utah invented a prototype handset due to his inability to hear religious sermons on Sundays. Presented to the US Navy for testing. Wireless Specialty Apparatus Co., in partnership with Baldwin Radio Company, has set up a manufacturing facility in Utah to fulfill orders.
Headphones originated from the handset of the telephone receiver, and this was the only way to listen to electrical audio signals before the development of loudspeakers.
These early speakers used moving iron drivers, with single-ended or balanced armatures. Common single-ended voice coils are wound around permanent magnet poles, which are placed near a flexible steel diaphragm. The sound current through the coils changes the magnetic field of the magnet, which exerts a variable force on the diaphragm, causing it to vibrate, creating sound waves. The high sensitivity requirement meant no damping was used, so the frequency response of the diaphragm had large peaks due to resonance, resulting in poor sound quality. These early models lacked padding, and were often uncomfortable to wear for extended periods. Headphones used in telegraph and telephone work have an impedance of 75 ohms. Those used with early wireless radios had more fine wires to increase sensitivity. Resistance from 1000 to 2000 ohms was common. Some very sensitive headphones, such as those made by Brands circa 1919, were commonly used for early radio work.
In 1958, John C. Koss, a jazz musician from Milwaukee, produced the first stereo speakers. Smaller earbuds, which plug into the user's ear canal, were first developed for hearing aids. It became widely used with transistor radios, which appeared commercially in 1954 with the introduction of the Regency TR-1. The most famous audio device in history, which allowed people to listen to the radio anywhere. The earphone uses either a moving iron armature or a piezoelectric crystal to produce the sound. The 3.5 mm connector was used, which is the most widely used in portable applications today.
The method of work
Headphones work in the same way as regular headphones based on the idea of (in English: voice coil) when an electric current passes through a coil of thin wire located in a magnetic field, the coil begins to move, and with the special design of the speaker the coil moves in and out, and a membrane is pasted on this coil The membrane vibrates, generating turbulence in the air, creating the original sound.
species
Headset size can affect the balance between accuracy and portability. In general, headphone shape can be divided into four separate categories: circumferential (over-ear), supra-aural (over-ear), earphone and in-ear.
Surround headphones
Surround headphones (sometimes called full-size headphones or over-the-ear headphones) have circular or oval-shaped earpads that cover the ears. Because these headphones surround the ear completely, circumaural headphones can be designed to seal completely against the head to reduce outside noise. Due to their size, surround headphones can be heavy and there are some sets that weigh over 500g (1lb).
Over-ear headphones
Over-ear headphones or on-ear headphones have pads that press against the ears, not around them. They were generally 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 external noise. Ultrasonic headphones can also cause discomfort due to pressure on the ear compared to around-the-ear headphones.