How is the decibel defined What does the decibel mean?

What does decibel mean for sound?

Decibels, which are the units of magnitude of the sound pressure level (symbol: dB).

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A decibel is a unit of measurement that measures the ratio of two quantities of the same unit, and is mainly used to measure the intensity of sound.

Specifically, there are three interpretations: 1. A unit that expresses the ratio of two electric or sound powers, which is equal to 10 times the commonly used logarithm of the power ratio.

2. A unit that expresses the ratio of two voltage or current values or similar sound quantities, equal to 20 times the commonly used logarithm of the voltage or current ratio.

3. A unit for measuring the relative loudness of sound, approximately equal to the minimum value of the difference in loudness that the human ear can normally perceive, and the range of the difference in loudness that the human ear can perceive includes approximately 130 decibels on a scale starting with the faintest audible sound as 1.

Decibels usually refer to current squared, voltage squared, particle velocity squared, sound pressure squared, displacement squared, velocity squared, acceleration squared, force squared, amplitude squared, field strength, and sound energy density.

1. A unit that expresses the ratio of two electric or acoustic powers, equal to 10 times the commonly used logarithm of the power ratio, abbreviated as db;

2. A unit that expresses the punch-bending imitation ratio of two voltage or current values or similar sound quantities, which is equal to 20 times the commonly used logarithm of voltage or current ratio of loose fiber;

3. A unit for measuring the relative loudness of sound; Equal to the minimum value of the difference in loudness that can normally be perceived by the human ear; The range in which the human ear can perceive the difference in loudness ranges from 1 dB to 130 dB for the faintest audible sound.

55 decibels is equivalent to the sound of a desktop computer running on the host.

Generally speaking, 20-40 decibels is about a whisper in the ear; 40-60 decibels is a normal conversation sound; More than 60 decibels is in the noisy range; 70 decibels can be considered noisy and begin to damage the hearing nerve; Above 90 decibels can cause hearing damage.

** of the decibel concept.

In acoustics, it is customary to use decibels to represent the loudness of sound, and the so-called loudness of sound is related to sound pressure, that is, the pressure difference of sound waves, and the unit is Pascal. The sound pressure that can be felt by the human ear is not more than 20,000 Pa, and the lowest sound pressure that can be felt is about Pa, which is very inconvenient to describe in daily life, so the concept of decibels was introduced.

The so-called Bell value of sound pressure is the logarithm of sound pressure and then multiplied by 2. In daily life, in fact, we rarely encounter the so-called limit sound pressure, and the number of bells in the general environment is about 8-13. If the bell is used to represent the magnitude of the sound is still very rough, the scientists have introduced the decibel number.

Scientists divided each bel interval into 10 parts, each representing a different intensity and sound pressure, or decibels.

During the day, it is above 55 decibels, and at night it is above 45 decibels.

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