Velleman VDSPRO18B User Manual
Page 2
VDSPRO18B
2
VELLEMAN
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All modifications of the device are forbidden for safety reasons.
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Operate the device in the way described in this manual and only use the device for its intended purpose. All other
uses may lead to short circuits, burns, electroshocks, hearing loss, etc. The warranty automatically becomes void
in case of improper use.
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The figures in this manual describe the VDSPRO18B. Other models and their features are comparable with the
VDSPRO18B.
5. Legal Provisions
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Operating an amplification system can produce extremely high noise levels that may cause permanent hearing
loss. The legal instructions for using an amplification system vary from country to country. The user is responsible
for respecting the legal provisions applicable in his country.
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Always monitor the sound pressure level when operating an amplification system in discos, concerts etc. Never
exceed the permissible noise level as specified by the law.
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Hearing damage caused by high noise levels can be regarded as a physical injury and may lead to criminal
prosecution.
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Please note that the organiser is responsible for respecting maximum noise levels.
6. Information on Hearing Loss
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More and more younger people suffer from hearing loss of 25dB or more, mainly caused by listening to loud
music. Every person operating amplification systems should know to what sound pressure levels he is exposed
to. In a discotheque, average levels of 75dB to 105dB are reached. At a rock concert, the sound pressure levels
can rise from 95dB up to 115dB. Individual peaks can exceed the 130dB pain level. Such levels are typical for
e.g. motor chain saws.
An Overview on the Different Noise Levels
10dB – Heartbeat
25dB – Whisper
40dB – Average home
50dB – Light traffic
60dB – Normal conversation
70dB – Vacuum cleaner
80dB – Telephone ringing
90dB – Pneumatic drill
100dB – Power mower
120dB – Boom box in car
130dB – Pain level
140dB – Jet plane 30m overhead
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It is important to know that a 3dB increase will double the sound level. The human hearing only recognises a
doubling of the sound level when the noise level is increased by 10dB. Hearing loss does not depend on the
sound level but on the noise level and starts way before than the pain level.
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Many a one deceives himself by thinking that noise is something you can get accustomed to. Nothing is further
form the truth!
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The reason why some people have got accustomed to a certain noise level and are no longer disturbed, is that
they have already suffered hearing loss. The damage makes the hearing insensitive to the frequencies forming
the loudest part of the noise. Getting accustomed to noise does not mean anything other than trying to get along
with hearing loss in everyday life. Hearing loss cannot be recovered and can only be compensated with hearing
aids. Subjectively, hearing loss feels like having dampened ears. This effect weakens with time but loss in hearing
sensitivity is permanent.