Sennheiser HMEC 45-CA NoiseGard, Instructions For Use Manual

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140 dB Jet engine (at a distance of 25 m)
130 dB Aircraft engine (This is the treshold of pain)
120 dB Pneumatic drill
110 dB Blacksmith's Hammer, concrete works
100 dB Die-cast machine
90 dB Metal workshop
80 dB Tractor
70 dB Office
60 dB Conversation
50 dB Ambient noise
40 dB Living room
30 dB Library
20 dB Bedroom
10 dB Forest, no wind
The unit of sound levels is the decibel (dB). A noise reduction of 10 dB is generally perceived as halving of
the loudness, another 10 dB decrease corresponds to a loudness reduction of 75 %, and so on.
loud
quiet
The problem of noise
The negative effects of noise pollution have been proven by studies, and everybody
will have experienced them:
왘
Nervousness
왘
Lack of concentration
왘
Irritability
And these are only the most obvious effects on the human body. Noise also affects
the autonomic nervous system and can lead to permanent hearing damage.
There are a multitude of noise sources, and the individual very often has no
influence over them. The only solution when being in a noisy place is protecting
oneself against ambient noise. These noise problems are particularly prevalent in
an aircraft cockpit where a pilot often has to have the communications headset so
loud as to risk permanent hearing damage.
With the
NoiseGard ®
system, Sennheiser has come up with an effective solution.
These operating instructions explain the
NoiseGard
®
principle and show you how
to use the
NoiseGard
®
headset.
Noise levels