1. What is the Sound Intensity Formula?

The sound intensity formula calculates the intensity of sound at a given distance from the source. It describes how sound energy spreads out in a spherical pattern from a point source in a free field.

2. How Does the Calculator Work?

The calculator uses the sound intensity formula:

Where:

• \( I \) — Sound intensity (W/m²)
• \( P \) — Sound power (W)
• \( r \) — Distance from source (m)
• \( \pi \) — Mathematical constant pi (≈3.14159)

Explanation: The formula shows that sound intensity decreases with the square of the distance from the source (inverse square law).

3. Importance of Sound Intensity Calculation

Details: Calculating sound intensity is crucial for acoustic engineering, noise control, audio system design, and environmental noise assessment.

4. Using the Calculator

Tips: Enter sound power in watts and distance in meters. All values must be valid (power > 0, distance > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why does intensity decrease with distance squared?
A: Because sound energy spreads out over the surface area of a sphere, which increases with the square of the distance.

Q2: What are typical sound intensity values?
A: Human hearing range: 10⁻¹² W/m² (threshold) to 1 W/m² (pain threshold). Conversational speech is around 10⁻⁶ W/m².

Q3: Does this formula work for all sound sources?
A: It works best for point sources in free field conditions. For directional sources or in enclosed spaces, additional factors must be considered.

Q4: How does intensity relate to sound pressure level?
A: Sound intensity level (SIL) in dB = 10·log₁₀(I/I₀), where I₀ = 10⁻¹² W/m² is the reference intensity.

Q5: What are the limitations of this formula?
A: Assumes ideal spherical spreading, no reflections or absorption, and a point source. Real-world conditions may require corrections.