00030129.DOC, Version 1.0
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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!
5. DESCRIPTION
5.1 Features
Headphone amplifier, 6 channels
The
OMNITRONIC HPA-6
is a 6-channel headphone amplifier that can be operated in mono or stereo
mode. This unit enables to amplify audio signal with line level (e.g. of CD/MP3/MD/DVD players, tape decks,
mixers or PCs) for the reproduction via up to six headphones. A different input signal can be fed via the
inputs DIRECT IN to each channel. Furthermore, two stereo input signals or four mono input signals at the
MAIN IN and AUX IN jacks can be distributed to several channels.
• Distributes the signal of up to two stereo or four mono audio sources to up to 6 sets of headphones
• 6 channels with separate level controls and headphone outputs
• Each channel with additional input to isolate it for specific input signals
• Master signal input (e.g. CD player, mixer, PC, etc.) via stereo jack (front) or two mono jacks (rear)
• Aux input for connecting a second audio source (mixed to the master source)
• Mono/stereo switch and Pan control for the master signal
• All connections via 6.3 mm (1/4") jacks
• 19" dimensions for rack installation, 1 U
The
HPA-6
is designed for professional application. The connectors are located on the front and rear
panel; the level controls are on the front panel. Channels 1 to 6 are identical.
