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Information on hearing loss

March 14th, 2013 Posted in OMNITRONIC, worth knowing Tags: , ,

More and more young people suffer from hearing loss of 25 decibel or more, mainly caused by loud music from portable MP3 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 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.

To prevent damage to the human ear at events, many of our customers already use a guard system for limiting the sound pressure level. The sound pressure level (SPL) guard system Omnitronic SPL-1 consisting of a 2-channel limiter with measurement microphone and external warning indicators (optional) serves for meeting legal noise regulations e.g. in discotheques or during events. The system is inserted in the audio chain between the source (mixer or controller) and the amplifier(s) and guarantees that a certain preset level will not be exceed with the connected PA system.

The limiter uses an omnidirectional measurement microphone to continuously measure the current sound pressure level of a speaker system within a frequency range of 20 Hz to 20 kHz. When the level is exceeded, the limiter attenuates the output signal to the value adjusted with the threshold control.

Additionally or alternatively to the limiter operation muting can be switched on. The muting is activated when the level is exceeded for more than 60 seconds. Then all outputs will be shut off for 30 seconds. The unit features 3-color LED indicators to warn of an impending muting and offers two outputs for the external warning indicators (optional) which can be installed near the DJ or behind the bar to give a clear impression of the warning situation.

To prevent manipulation all audio connectors and controls can be sealed.

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