Finding your perfect headset

There are an increasing number of military grade headsets available, and with such a wide array of features, benefits and styles, it can be difficult to select the best headset for your application.

If the headset selection process has been approached as a ‘one solution must fit all’ then one hopes the worst case noise environment has been considered.

The headset must deliver clear and concise audio communication in the environment where it will be ultimately used, whilst protecting the wearer from harmful levels of noise, and also be comfortable to use for extended periods. The headset protects the user from continuous noise, such as vehicle noise, and short duration impulse noise, such as explosions or gunshots.

Passive headsets are good at attenuating impulses and higher frequencies, such as engine whine noise, but are less effective with lower frequencies. For medium and high noise applications, attenuation must be supplemented with electronic Active Noise Reduction (ANR) attenuation, which is most effective at the lower frequencies - attenuating the rumble and rattle. As a general rule, the noisier the environment, the more attenuation is required, the bigger the headset will be. Conversely, smaller and lighter solutions can be used in quieter environments.

First consideration – Noise profile. The starting point in the selection process is to know in detail the noise profile in the intended environment. Not all headsets have the same performance levels, even if they appear to have similar or even identical Noise Reduction Ratio (NRR) attenuation in dB(A). Differences in attenuation levels at some spot frequencies can be significant between makes and models, up to three times better or worse at some frequencies – so this could be critical if there is a high noise content at these frequencies in the intended application. Having the full noise envelope data is invaluable in the selection process.

For low noise environments, there may be no requirement for attenuation, so selection can be made on the basis of performance and comfort, such as a lightweight on-the-ear headset.

In low to medium noise environments, such as wheeled vehicles, noise levels are generally high enough to warrant some attenuation – sometimes Passive ear defenders can be sufficient. There are many Circumaural (over-the-ear) and in-the-ear solutions that provide these levels of protection.

In medium to high noise environments, such as tracked or wheeled light armoured vehicles, noise levels are generally too high for Passive attenuation to be fully effective, so this must be supplemented with electronic Active Noise Reduction (ANR) attenuation, which is most effective at the lower frequencies - attenuating the rumble and rattle. Only Circumaural headsets can provide these medium to high attenuation levels.

In high noise environments, such as tracked vehicles or in aviation, high levels of passive and active attenuation is required, with ANR providing enhanced hearing protection. Higher attenuation levels invariably mean that the ear shells become larger, have higher clamping forces, are heavier and are therefore less comfortable.

Next consideration: Compatibility. The headset must be compatible with other items of personal protection equipment - such as ballistic helmets and body armour. The size and shape of the ear shells must be designed to fit the available space envelope, whilst giving the desired acoustic performance. (Passive attenuation, when employed in high noise applications is, among other things, a function of ear shell volume, ear cushion compliance, clamping pressure and headset mass). If a standard off-the-shelf headset can’t meet the attenuation criteria, work with your headset manufacturer to customise the construction.

Next consideration: Wearing Style. For Circumaural headsets there are many choices of head bands, head straps, neck bands and many other configurations to suit comfort and compatibility needs, and the consistency of acoustic seal integrity between ear cushions and the head is paramount. There may be a need to fit or remove the headset without taking off the ballistic helmet, which could further restrict the choice. Importantly, whichever style is selected, including light weight and in-the-ear headsets, these should to be assessed for comfort by the individuals who will be wearing them.

These are just a few of the many considerations in the headset selection process.