This tool is often used for EIA calculations.

Definition of sound pressure level:

The effective value of the sound pressure is logarithmically expressed to indicate the strength of the sound. This value indicating the strength of the sound is called the sound pressure level.

The sound pressure level is expressed by the symbol SPL in decibels (dB)

$$ SPL (sound pressure level) = 20 lg \frac{P _e}{P _ref} $$

* P_e---effective value of sound pressure to be tested   * P_ref----Reference sound pressure, the reference sound pressure in air is generally 2*10   * ^-5P_a.

Note: Since the minimum sound pressure that can be felt by human ears is 20μP_a, people use this pressure as the reference standard for sound pressure and record it as P_ref.

$$ 20μP_a=0dB.SPL $$

Therefore, 20 μPa = 0 dB. SPL is defined acoustically or medically as a hearing threshold (YU), ie an audible valve. Only above this value will the valve open and hear the sound.

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