Ear Defenders
By Indy M
Ear muffs (Wiki) or also known as acoustic ear defenders are objects very similar in shape with modern day headphones but instead of being used to listen to audio sounds are used as protection for one's ears. These earmuffs or ear defenders can be made from several materials ranging from thermoplastic (Wiki) to metal in the form of a headband to be fitted on the top of the head with a pad at each end to cover the outer parts of the ear.
Earmuffs were first made in 1873 by a son of a bridge builder, Chester Greenwood whose prototype involved loops of wire with tufts of fur sewn onto them by his grandmother. As such, since patenting this invention, he has been not only manufacturing them for the 60 years before he passed but also provided large job opportunities for many individuals especially women who were more accomplished at sewing than men. Today, this invention of his has come a long way from its fur and wire ancestor with modern earmuffs coming in two basic kinds.
Both of these are thermal earmuffs and acoustic earmuffs and are both designed for separate purposes. Thermal earmuffs as most people would know is worn primarily in cold environments such as during winter in countries with four seasons or even countries with round the year cold climates such as Antarctica as a method to keep the ears warm as exposed skin to such elements are highly undesirable. These earmuffs are usually manufactured with thermoplastic for the frame and the pads are usually made with fur-like material so as to provide maximum insulation.
Acoustic earmuffs or ear defenders on the other hand, are worn mainly as a protection from extreme noises and are generally similar to thermal earmuffs except instead of pads to keep the ears warm, they have two cups made of sound deadening material on each side. This is especially useful when working in environments where one is exposed to unhealthy doses of extremely loud and sharp noises as prolonged exposure tend to lead to hearing impairment as well as a multitude of other conditions. This can be seen in many jobs such as construction sites where workers may need to use equipment such as pneumatic drills in small enclosed areas, explosives in demolition work and firing of firearms in firing ranges.
Acoustic earmuffs are generally made with a hard thermoplastic or metal for the frame and uses acoustic foam which increases the air resistance to reduce the amplitude of these sound waves as a method to absorb the incoming noise. However, today, manufacturers have come with many additions to the conventional acoustic earmuff such as combining a headphone with the earmuff so as to allow the wearer to listen to music or even be used as a method of communication via radio or other transmission methods while providing protection.
There are also many earmuffs designed to be attached to hard hats or safety helmets so as to function to protect both the ear and head of the wearer. Some acoustic earmuffs also integrate the use of DRC (Dynamic Range Compression) where the ear defenders are outfitted with microphones to pick up noises in the background which allow the wearer to hear normal sounds while attenuating louder sounds.
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