1. What is the Inverse Square Law?

The Inverse Square Law describes how sound pressure level decreases as distance from the sound source increases. For every doubling of distance from the source, the sound pressure level decreases by approximately 6 dB.

2. How Does the Calculator Work?

The calculator uses the Inverse Square Law formula:

Where:

• \( SPL_1 \) — Reference sound pressure level (dB)
• \( SPL_2 \) — Calculated sound pressure level (dB)
• \( r_1 \) — Reference distance from source (m)
• \( r_2 \) — Target distance from source (m)

Explanation: The formula calculates how sound pressure level changes with distance from a point source in a free field environment.

3. Importance of Sound Pressure Level Calculation

Details: Accurate SPL calculation is crucial for noise control, acoustic design, hearing protection, environmental noise assessment, and audio system planning.

4. Using the Calculator

Tips: Enter reference SPL in dB, reference distance in meters, and target distance in meters. All distance values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: Why does sound decrease by 6 dB per distance doubling?
A: Because sound energy spreads over a surface area that increases with the square of the distance from the source.

Q2: Is this accurate for all sound sources?
A: This applies best to point sources in free field conditions. Line sources and complex environments may show different attenuation patterns.

Q3: What are typical reference distances?
A: Common reference distances include 1 meter for equipment noise or specific distances where measurements were taken.

Q4: Does this account for environmental factors?
A: No, this is for ideal free field conditions. Real-world factors like reflections, absorption, and atmospheric conditions affect actual SPL.

Q5: Can this be used for indoor calculations?
A: Indoor calculations are more complex due to reflections and room acoustics. This calculator provides theoretical free field values.