Created By : Naaz Fatima

Reviewed By : Phani Ponnapalli

Last Updated : Apr 10, 2023

This Distance Attenuation Calculator is a user-friendly tool that helps to analyze how sound propagates in the air fastly. You need to enter the distance from the source and sound pressure level and tap the calculate to get the Sound Level Difference as output.

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Steps to Compute Sound Pressure Level

Follow the steps listed below to determine the sound pressure level (SPL) and difference in SPL easily and effortlessly:

  • Get the sound pressure level at point 1, distance from the sound source to two points.
  • Apply the log function to the division of distance from sound source to point 2 to distance from source sound to point 1.
  • Multiply the obtained value by 20.
  • Subtract sound pressure level at point 1 from the product to get the SPL at point 2.

Sound Attenuation - Inverse Square Law

SPL stands for Sound Pressure Level. Sounds are nothing but vibrations in the air and those apply pressure on our ears. To measure these sound pressures we use units called decibel (dB) scale in the algorithm.

Sound attenuation explains how the sound pressure level changes with increasing distance from the source sound. To calculate sound attenuation, we can inverse square law.

The sound attenuation formula is

SPLΓéé = SPLΓéü - 20 * log (RΓéé / RΓéü)


SPLΓéü is the sound pressure level at the point 1

SPLΓéé is the sound pressure level at point 2

RΓéü is the distance from the sound source to point 1

RΓéé is the distance from the sound source to point 2


Question: Let us say two persons standing close to the bus stand. The distance between person 1 to the bus stand is 10 m, and the distance between person 2 and bus stand is 15 m. The sound pressure level at person 1 is 20 db. What is the SPL at person 2 and difference in SPL?


Given that

The distance from person 1 to bus stand is RΓéü = 10 m

The distance from person 2 to bus stand is RΓéé = 15 m

Sound pressure level at person 1 is SPLΓéü = 20 db

Sound attenuation formula is SPLΓéé = SPLΓéü - 20 * log (RΓéé / RΓéü)

SPLΓéé = 20 - 20 * log(15/10)

= 20 - 20 * log(3/2)

= 16.478 dB

The difference in sound pressure level = SPLΓéü - SPLΓéé

= 20 - 16.478

= 3.522

Therefore, SPL at person 2 is 16.478 and sound level difference is 3.522 dB.

Obtain detailed solutions for your physics questions on sound attenuation with our Distance Attenuation Calculator. Check all our online calculators on physics from Physicscalc.Com & improve your skills and understand the topic.

Frequently Asked Questions on Sound Attenuation Calculator

1. How do you define sound attenuation?

Sound attenuation is nothing but the loss of energy from the sound waves. Attenuation means the loss of energy. When the sound passes through different objects in different ways it shows the impact on its quality. It means sound quality reduced when it travels through more objects.

2. What does attenuation affect sound waves?

If a wave travels through a medium, its intensity decreases with the distance. The combined effect of scattering and absorption is attenuation. Absorption is converting wave energy into other energy. Scattering is the reflection of a wave in the opposite of the original direction.

3. How to calculate Noise Attenuation?

To calculate the noise attenuation, we use inverse square law. You may also enter the details in the Sound Attenuation Calculator to get the result.

4. What is the formula to find the distance attenuation?

The simple formula to calculate the sound pressure level at the 2nd point is SPLΓéé = SPLΓéü - 20 * log (RΓéé / RΓéü).