1. What is the Noise Level Equation?

The noise level equation \( L_2 = L_1 - 20 \log_{10}(r_2 / r_1) \) calculates the sound pressure level at a distance r2 based on the known level L1 at distance r1. This equation accounts for the inverse square law of sound propagation.

2. How Does the Calculator Work?

The calculator uses the noise level equation:

Where:

• \( L_1 \) — Initial noise level at distance r1 (dB)
• \( L_2 \) — Calculated noise level at distance r2 (dB)
• \( r_1 \) — Initial distance from sound source (m)
• \( r_2 \) — Target distance from sound source (m)

Explanation: The equation demonstrates how sound levels decrease with increasing distance from the source, following the inverse square law.

3. Importance of Noise Level Calculation

Details: Accurate noise level prediction is crucial for environmental noise assessment, workplace safety regulations, acoustic engineering, and noise control planning.

4. Using the Calculator

Tips: Enter the initial noise level in dB, both distances in meters. All values must be valid (distances > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why does noise decrease with distance?
A: Sound energy spreads out over a larger area as distance increases, following the inverse square law, which results in lower sound pressure levels.

Q2: What are typical noise level ranges?
A: Normal conversation is about 60 dB, city traffic 85 dB, rock concert 110-120 dB, and jet engine at close range 140+ dB.

Q3: When is this equation most accurate?
A: This equation works best for point sources in free field conditions without reflections, obstacles, or atmospheric absorption effects.

Q4: Are there limitations to this equation?
A: The equation assumes ideal conditions and may not account for reflections, atmospheric absorption, ground effects, or directional sound sources.

Q5: How does frequency affect noise propagation?
A: Higher frequency sounds attenuate more quickly with distance due to atmospheric absorption, while lower frequencies can travel farther.