This is by far the risk to which everyone is most frequently exposed, even outside of shows.
That's why we strictly apply the decree of August 07, 2017 No. 2017-1244 on the prevention of risks related to noise and amplified sounds.
When it comes to sound some explanations are in order!
Our two ears are placed on both sides of the head. They are about 17 cm apart (15 to 20 cm).
Because of the speed of sound which travels at 340 meters/second, we notice that there is a time shift in the arrival of the sound between the right ear and the left ear. This time shift is interpreted by the brain to locate the origin of a sound on the horizontal plane. It is the basis of stereophony.
Thus, the placement of sounds in the stereophonic space that we usually practice with the panning by playing on the difference in volume between the two speakers allows an imperfect positioning since we always have two sound sources instead of one.
In order to avoid irreversible damage to hearing, it is necessary to wear hearing protection (disposable earplugs, for example) and to limit the time of exposure to high sound levels.
The brain's interpretation of sound is called psychoacoustics.
The brain does not interpret sound objectively. There are two important phenomena to consider: the masking effect and isosony:
The mask effect occurs when one sound has a greater volume than another. Rather than hearing both sounds perfectly at different volumes, the louder one is heard, but the softer one becomes difficult to distinguish because it is masked by the other. For example, if someone is talking to you in a nightclub, you cannot hear them because of the ambient noise.
However, the sound is there and you should be able to hear it, but the difference in volume means that you are unable to concentrate your listening on the faintest sound. Furthermore, low-pitchedsounds also tend to mask high-pitched sounds.
Isosony concerns the response curve of the ear. Indeed, we do not perceive in the same way the bass, the mediums and the highs with identical volumes.
This phenomenon has its origins in our early childhood. It is a certain culture of the ear: the maximum of sensitivity is situated around 1000 Hz, which corresponds to the voice of the mother perceived while the baby is in its belly, then of its own voice.
Exposure to very high noise levels can result in permanent hearing loss. Sensitivity to this damage varies from individual to individual, but everyone is subject to extreme hearing damage in the presence of high noise levels.
Scientists believe that any exposure above these limits will result in hearing damage. To avoid dangerous exposure to high sound levels, it is advisable to use hearing protection. Hearing protectors should be worn when using equipment that produces high sound levels to avoid irreversible hearing loss.
Here again, at the show level, it is important not to do anything: Sound engineer is a profession!!!