Noise Reduction
There are compelling reasons for achieving noise reduction in
military environments because of the high sound levels that
frequently prevail. Noise can severely impair communication;
at best it is fatiguing and can cause short term hearing
impairment, at worst, it can lead to permanent hearing damage.
Health & safety, soldier effectiveness and mission success can
all be compromised by noise.
Levels can range anywhere from the medium
noise found in tactical wheeled vehicles, typically mid-90 dB(A),
to high levels over 110 dB(A) in tracked vehicles, to extreme
levels approaching 150 dB(A) experienced by ground crews working
around fast jets. As a ‘medium level’ of 95 dB(A) is actually
high in civilian workplace terms, it is understandable why clear
communication at higher military noise levels is so crucial.
Noise reduction is the attenuation of sound
energy reaching the ear, achieved through either the creation of a
physical barrier that stops the energy, known as Passive Noise
Reduction (PNR), or by so-called anti-noise techniques
called Active Noise Reduction (ANR) or even a combination of the two.
In the case of a communication headset, noise
reduction, in its simplest form, is typically achieved by blocking
the noise path using earcups sealed to the head by means of a
soft earcushion.