00031120.DOC, Version 1.0
19/25
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!
4. DESCRIPTION OF THE DEVICE
4.1 Features
High-power amplifier
• Class H technology
• Power supply with softstart
• High impulse stability
• Stable metal housing, light and compact
• Plain design with aluminium front panel
• 19" dimensions with 2 units
• Complete protection set against overheat, overload, short-circuit, DC, softstart
• Electronically balanced inputs via XLR mounting sockets
• Outputs via lockable Speaker-plugs
• Operation mode visible via LED display for Signal, Protect and Clip
• Calibrated input controls for exact level control, power switch
• Ground Lift switch against humming
• Bridged switch for bridging
• 30 Hz Low Cut on the rear panel
• Combines superior sound quality with highest reliabilty at significant lower weight
• Stable permanent power for all models
• Reliable power amp for a wide range of applications
