1. What is the Decibel Decrease Over Distance?

The decibel decrease over distance describes how sound intensity diminishes as it travels through space. The general rule is that sound decreases by 6 dB for each doubling of distance from the source in free field conditions.

2. How Does the Calculator Work?

The calculator uses the decibel decrease formula:

Where:

• \( d_1 \) — Initial distance from sound source (meters)
• \( d_2 \) — Final distance from sound source (meters)
• 6 — The dB decrease per distance doubling factor

Explanation: The equation calculates how much the sound level decreases when moving from distance d₁ to distance d₂ from the sound source.

3. Importance of Decibel Decrease Calculation

Details: Understanding sound attenuation over distance is crucial for audio engineering, noise control, environmental noise assessment, and sound system design.

4. Using the Calculator

Tips: Enter both distances in meters. The calculator will determine the decibel decrease between these two points. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Is the 6 dB per doubling rule always accurate?
A: This applies to ideal free-field conditions. In real environments, reflections, absorption, and other factors may alter the decrease.

Q2: Why does sound decrease by 6 dB per distance doubling?
A: Because sound energy spreads over a larger area (inverse square law), resulting in a 6 dB decrease for each doubling of distance.

Q3: Does this apply to all frequencies equally?
A: Higher frequencies may attenuate more quickly due to atmospheric absorption, especially over long distances.

Q4: How does this relate to perceived loudness?
A: A 6 dB decrease represents a noticeable but not dramatic reduction in perceived loudness (about half as loud).

Q5: What about indoor environments?
A: Indoors, reflections and reverberation can reduce the distance attenuation, making the decrease less than 6 dB per doubling.