User`s manual

00025663.DOC, Version 1.1
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Overview on the different noise levels
10 dB Heartbeat
80 dB Heavy traffic or telephone ringing
20 - 30 dB Whisper 90 dB Pneumatic drill
40 dB Average home 100 dB Power mower
50 dB Light traffic 120 dB Boom box in car
60 dB Normal conversation 130 dB Pain level
70 dB Vacuum cleaner 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 recognizes a doubling of the sound level when the noise level is increased by 10 dB. Damaging the
hearing does not depend on the sound level but on the noise level and starts way before 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 insensitive to those frequencies
forming the loudest part of the noise. Getting accustomed to noise does not mean anything other 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!
6. START-UP
This speaker-system must only be connected with an appropriate power amplifier (enclosed). The amplifier
power must correspond with the speaker-system power. An amplifier with too little power can also destroy a
speaker-system with a higher power range.
6.1 Choosing an appropriate power amplifier
The power amplifier included in the delivery is a 4-ohms mono amplifier.
The enclosed speaker-systems are 8-ohms speaker-systems. This is why only one speaker-system per
Speaker-socket must be connected. The total connected impedance must always be higher than 4 ohms.
When connecting further speaker-system pairs (e.g. 3 pairs) to the same power amplifier, the impedance
lowers even further. You must always make sure that the power amplifier is qualified for the new impedance.
If the impedance of the speaker-system is lower than the lowest allowed amplifier impedance, the amplifier
and the speaker-systems may be damaged.
Calculation number of speakers – impedance
E.g. 1 speaker à 8 Ohm = 8 Ohm
2 speakers à 8 Ohm = 4 Ohm (parallel)
2 speakers à 8 Ohm = 16 Ohm (in line)
3 speakers à 8 Ohm = 2.66 Ohm (parallel), only for amplifiers capable of handling 2 Ohms
2 speakers à 8 Ohm = 24 Ohm (in line)
4 speakers à 8 Ohm = 2 Ohm (parallel), only for amplifiers capable of handling 2 Ohms
N.B.:
The input-impedance of the speaker-systems should at least be the same or even higher than the output-
impedance of the amplifier.