C_SERIES_ACTIVE.DOC
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Information on hearing loss
More and more young people suffer from hearing loss of 25 dezibel or more, mainly caused by loud music
from protable cassette recorders and CD-players or discotheques.
Everybody operating amplification systems should know to what sound pressure levels he exposes his or the
audience's hearing. As an average levels between 75 and 105 dB(A) in the discotheque or 95 and 115 dB(A)
at a rock concert are reached. Individual peaks can exceed the pain level at 130 dB(A). Such levels are
typical for motor chainsaws or jack hammers.
Overview on the different noise levels
10 dB
Heartbeat
20 - 30 dB Whisper
40 dB
Average home
50 dB
Light traffic
60 dB
Normal conversation
70 dB
Vacuum cleaner
80 dB
Heavy traffic or telephone ringing
90 dB
Pneumatic drill
100 dB
Power mower
120 dB
Boom box in car
130 dB
Pain level
140 dB
Jet plane 30 meters overhead
It is important to know that doubling the power increases the noise level by 3 dB. The human hearing does
only recognize a doubling of the sound level when the noise level is increasey by 10 dB. Damaging the
hearing does not depend on the sound level but on the noise level and starts way befor the pain level.
Many people deceive themselves by thinking that noise is something they can get accustomed to. It is
possible that a positive opinion of a certain noise can reduce the physiological reaction, but the slow impacts
on the inner hearing must not be neglected: over stimulation and continuous elimination of the Cortic organ's
hair cells.
The reason why some people have got accustomed to a certain noise level and are no longer disturbed is
that they have already suffered a hearing damage. This damage make the unsensitive to those frequencies
forming the loudest part of the noise. Getting accustomed to noise does not mean anything oter than trying
to get along with the hearing loss in everyday life. The hearing loss itself cannot be healed, it can only be
compensated by hearing aids.
Subjectively, the hearing loss feels like dampened ears. This effect weakens with the time, but a loss in
hearing sensitivity often remains.
In order to relax the hearing sufficiently, the noise level should not exceed 70 dB(A) for 10 hours. Higher
noise levels during this relaxing period can prevent the relaxation and promote a permanent hearing damage
(Tinitus) or hearing loss.
Therefore:
Whoever wants to maintain his hearing should use hearing protectors!
START-UP
This speaker-system is directly connected with the audio mixer.
Make sure that the power switch is set to "OFF". Before you connect the devices, all units have to be
switched off and the master-control is set to "0".
Choosing appropriate connection cables
The speaker-system must only be connected via a sufficiently dimensioned cable. Too thin cables lead to
cable heatup or enormous power loss and loss in sound-quality.
