Electronic Hearing Protection

Electronic Hearing Protection Can Prevent NIHL without Impeding Communication

  The danger posed by constant exposure to loud noises should never be underestimated. According to a WHO survey performed in 2011, some 24% of Americans aged between 20 and 69 demonstrated an audiometric pattern that is thought to be consistent with noise-induced hearing loss or NIHL. Some degree of auditory impairment is a natural consequence of aging and, as such, almost inevitable. By contrast, providing that suitable precautions are taken, NIHL is a wholly preventable condition. Commonly affecting workers required to operate in noisy environments, just a simple pair of earplugs could help reduce the risk. Far more effective, however, would be some form of electronic hearing protection.

Protecting the ears from the damage caused by excessive levels of noise requires nothing more sophisticated than a means with which to block the entrance to the ear canals. This can be achieved reasonably effectively with the aid of the pliable inserts known as earplugs. Unfortunately, however, they not only block the potentially harmful noise, but all incoming sound. This makes it necessary for the wearer to remove them whenever he or she may need to communicate with a colleague thus, once more, exposing themselves to the risk of NIHL.

A more effective barrier is provided by the use of ear defenders. Although these devices cannot really be compared with electronic hearing protection, being purely passive in their action, their supra-aural positioning means that they exclude the entry of external noise far more effectively than simple earplugs. The latter fact is of particular importance in the case of younger people, most of whom spend many hours listening to a mobile music player with the aid of earbuds. Because they are normally a rather poor fit, the earbuds still tend to admit significant levels of background noise. This, in turn, prompts the music lovers to turn up the volume to dangerous levels (greater than 85 dB), in order to eliminate the invasive external noise.

By contrast, electronic hearing protection devices employ some form of active attenuation technology. This means that, unlike its passive counterparts, this type of device does not solely rely on the use of acoustically non-conductive materials in order to dampen external sounds. Instead, some rely upon a technique known as dynamic range compression, while others make use of an alternative principle termed “noise cancellation”. In the former type, a built-in microphone picks up ambient sounds and utilises special circuitry to pass sounds of normal volume, such as speech, to an internal speaker, whilst simultaneously attenuating all of the louder noises.

In the second form of active electronic hearing protection, which is also fitted with a microphone and a speaker, an alternative circuit generates a signal that is 180 degrees out of phase with any excessively loud incoming sound. This acts to reduce its amplitude and, in effect, cancels out any potentially damaging extraneous sound.

While, on the surface, this clever, active technology might appear to render the humble earplug obsolete, this is not, in fact, the case. In practice, the main problem inherent in most of these more compact forms of hearing protection lies not in the absence of electronic attenuation, which can actually be added, but in their geometry. Apart from the fact that it interferes with workplace communication, the simple, over-the-counter type of product is highly unlikely to provide the perfect fit that is essential in order to exclude all extraneous noise.

Because the architecture of the external ear differs so much between individuals, the only way to ensure an accurate fit is to prepare a mould of each ear, and to use these as the templates from which to manufacture a totally personalised product. All that remains to ensure that these firmly fitting plugs are able to provide both effective hearing protection and as ease of communication is some form of electronic attenuation. The attenuator will need to be adjusted, so as to permit the wearer to participate in a conversation, without the constant need to remove his or her earplugs, which would then re-expose the wearer to the risk of NIHL.

As a component of a more comprehensive service, H.A.S.S. Industrial provides custom-made hearing protection in the form of a range of personalised earplugs with built-in electronic attenuators under our Noise-Ban brand. To ensure maximum efficiency, and as part of the service, each pair is tested for leaks, and the attenuator adjusted to meet the individual wearer’s auditory requirements.

While you might think that you will not need hearing protection if you don’t work in noisy environments like the construction or mining industries, this couldn’t be further from the truth. Our products are particularly suitable for the protection against impact noise, such as the type of noise that you will be exposed to while hunting or watching a fireworks display. Contact us today for more information about how to protect your hearing.

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