Education, The science
Volume of sound: the difference between dream, background and decibel
Sound waves, affecting the human eardrum, cause vibrations of the hairs. The amplitude of these sound waves is directly related to the perceived loudness of these waves - the more it is, the more loud the sound will be felt. This, of course, is a simplified interpretation. But the essence is clear!
The unit of sound volume is called sleep (sone). 1 sleep roughly corresponds to the volume of the muffled conversation, and the volume of the aircraft engines is 264 sleeps. By definition, 1 sleep is equal to the volume of a tone at 1000 and a level of 40 dB. The power of sound, expressed in sones, has the formula:
J = k * I 1/3 , here
K is a frequency-dependent coefficient, i is the intensity of the oscillations.
Due to the fact that vibrations with different sound pressure (differing in their intensity) at different frequencies can have the same loudness of sound, to evaluate its strength, also a unit such as the background (phon) is used. 1 F is equal to the difference in the volume levels of 2 sounds with the same frequency, for which the same loudness sounds with a frequency of 1000 Hz will differ by the level of pressure (intensity) by 1 decibel.
During the day, the human ear can hear sound waves with a loudness of 10 decibels and higher. It is considered that the maximum range of all frequencies available to a person is 20-20,000 Hz. It is noticed that it changes with age. In youth, it is best to hear mid-frequency waves (about 3 KHz), in adulthood - frequencies from 2 to 3 kHz, and in old age - sound at 1 KHz. Sound waves with an amplitude of up to 1-3 KHz (the first kylogers) are included in the zone of verbal communication. They are used in broadcasting on DV-and SV-bands, as well as in telephones.
To determine the volume of sound or noise, a special device is used - the noise level meter . It helps to find out whether the sound oscillations exceed the maximum permissible value, which does not pose a danger to man. If a person is exposed to waves with a level exceeding 80-90 dB for a long time, this can cause complete or partial hearing loss. At the same time, pathological disturbances can occur in the nervous and cardiovascular systems. The safe volume is limited to 35 dB. Therefore, to preserve the hearing, you should not listen to the music in the headphones at full volume. Being in a too noisy place, you can use ear plugs.
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