The physical characteristic of the volume of sound is the level of sound pressure, in decibels (dB). A person in the daytime can hear sounds with a volume of 10-15 dB or higher. The maximum frequency range for the human ear, on average – from 20 to 20,000 Hz. In youth, a medium frequency sound with a frequency of 3 kHz is better heard, in average age – 2-3KHz, in old age – 1KHz. Such frequencies are common in phones and on the radio. With age, the audible range is narrowed: for high-frequency sounds – decreasing to 18 kilohertz or fewer. For example, in older people every ten years, it narrows by about 1000 Hz, and for low-frequency ones, on the contrary, it increases from 20 Hz or more.
To understand what decibels will be with a particular sound, we give some examples. The sound level of 10 decibels corresponds to a quiet rustle of leaves. The level of 20 decibels will already be a quiet human whisper.
Most countries have established sanitary standards. For example, for residential premises, the maximum sound level at night is set at 30 decibels. But in the daytime in the living room, the optimal volume of sound is already considered 40 decibels. It is believed that such a sound in no way can negatively affect either the hearing or the psyche of a person.
European standards establish a sound standard of 55 decibels for offices. It’s pretty noisy. But, for example, for stores and offices a norm of 60 decibels has been established.
It is believed that the sound level of 65 decibels will have a loud conversation, and laughter and screams of 75 decibels. An extremely noisy level, but at the same time relatively safe for human hearing, is considered a level of 100 decibels. This is equivalent to thunder rolling, chainsaw operation or, for example, subway car noise when arriving at the station, if it is an underground room. It is the sound of 100 decibels that represents the maximum permissible sound pressure for the player’s headphones according to European or American standards.
If you stand next to a working punch hammer, you have to plug your ears. Otherwise, temporary partial hearing loss may occur. Enduring such a sound is almost unbearable.
But the sound of 130 decibels is already considered a pain threshold. This is the strength of the sound of a taking off jet passenger aircraft. Even a small excess of this parameter can lead to contusion of the human hearing aid.
With sound levels over 160 decibels – a rupture of the eardrums and lungs, a person, is possible. More than 200 decibels cause death. This is the threshold of the latest noise weapons.
140 decibels already unambiguously mean contusion. This, for example, is the sound of a take-off military jet at the edge of the runway, when it gives engines the maximum load to get off the ground.
The maximum permissible sound levels are more than «normal» by 15 decibels. For example, for residential rooms of apartments, the permissible constant sound level in the daytime is 40 decibels, and the temporary maximum is 55. With permanently operating engineering equipment – the correction is taken into account – minus 5.