HEAR OF HERO........

The sound of world can be hear in our ears. which change our mode to happiness.Lot of sound can give lot of emotions. In which that can be better feeling and a motivation .........If the sound get into our  ear directly , instead of speaker and voices...... 

HEADPHONES

Headphones originated from the telephone receiver 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.

These early headphones used moving iron drivers, with either single-ended or balanced armatures. The common single-ended type used voice coils wound around the poles of a permanent magnet, which were positioned close to a flexible steel diaphragm. The audio current through the coils varied the magnetic field of the magnet, exerting a varying force on the diaphragm, causing it to vibrate, creating sound waves. The requirement for high sensitivity meant that 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 long periods. Their  varied; headphones used in telegraph and telephone work had an impedance of 75 ohms. Those used with early wireless radio had more turns of finer wire to increase sensitivity. Impedance of 1000 to 2000 ohms was common, which suited both crystal sets and triode receivers. Some very sensitive headphones, such as those manufactured by Brandes around 1919, were commonly used for early radio work.

The Navy offered Baldwin some suggestions for a few tweaks, which he promptly incorporated into a new design that, while still clunky, was comfortable enough for everyday use. The Navy placed an order for Baldwin’s headphones, only to learn that Baldwin was building them in his kitchen and could only produce 10 at a time. But because they were better than anything else that had been tested, the Navy accepted Baldwin’s limited production capabilities. After producing a few dozen headphones, the head harness was further improved as its design was reduced to only two leather-covered, adjustable wire rods attached at each end to a receiver that supposedly contained a mile of copper wire.

Indeed, the entire history of the headphone seems to be one of incremental improvements on existing designs, starting as early as the 1880s, with the single over-ear receivers worn by telephone operators.

Innovations along the way from then to now include Eugen Beyer’s development of the first dynamic headphone in 1937. Dynamic headphones differ from other headphone technologies in that they rely on a stationary magnet and a moving cone to create sound, much the same way that speakers generate audio. It proved to be such a popular and practical design that most headphones—and most earphones—these days still rely on dynamic drivers, such as Phiaton’s BT 120 C neck band style earphones and the BT 390 on-ear foldable headphones.

Fast-forward a few decades and we come to one of the most popular innovations yet. In 1958, John C. Koss forever changed the music industry with the introduction of the first stereo headphones in response to the first commercially available stereo recordings, introduced the year before. As a result, headphones became less of a tool for the military and telecommunications industries and more of a personal music listening device. And the rest, as they say, is history.

THANKS FOR READING.........😎😎