Sound Absorption Coefficient Calculator
Calculate sound absorption coefficient (α)
Must be less than or equal to incident power
How to Use This Calculator
Enter Incident Power
Input the incident sound power (Pi) in Watts. This is the power of sound hitting the surface.
Enter Absorbed Power
Input the absorbed sound power (Pa) in Watts. This is the power absorbed by the material (must be ≤ incident power).
Calculate
Click calculate to get the absorption coefficient (α), which ranges from 0 (perfect reflection) to 1 (perfect absorption).
Formula
α = Pa / Pi
where α = absorption coefficient (0 to 1), Pa = absorbed power (W), Pi = incident power (W)
Example:
If incident power is 100 W and absorbed power is 30 W:
α = 30 / 100 = 0.300
This means 30% of the incident sound is absorbed, and 70% is reflected.
Note: Absorption coefficient depends on frequency. Materials typically have different α values at different frequencies. The value α = 1 means perfect absorption (no reflection), while α = 0 means perfect reflection (no absorption).
About Sound Absorption Coefficient Calculator
The Sound Absorption Coefficient Calculator determines the absorption coefficient (α) of a material, which measures how much sound is absorbed versus reflected. This coefficient ranges from 0 (perfect reflection) to 1 (perfect absorption) and is essential for acoustic design and material selection.
When to Use This Calculator
- Acoustic Design: Select materials for sound absorption
- Architectural Acoustics: Design acoustic panels and treatments
- Material Testing: Evaluate sound absorption properties of materials
- Room Acoustics: Calculate total absorption for reverberation time
- Noise Control: Design sound-absorbing surfaces
- Education: Learn about sound absorption and material properties
Why Use Our Calculator?
- ✅ Quick Calculations: Get absorption coefficient instantly
- ✅ Accurate Results: Uses standard acoustic formula
- ✅ Complete Information: Shows absorption, reflection, and coefficients
- ✅ Educational: Learn about sound absorption concepts
- ✅ Free Tool: No registration required
Understanding Absorption Coefficient
The absorption coefficient (α) quantifies how well a material absorbs sound. It's the ratio of absorbed power to incident power, ranging from 0 to 1.
- α = 0: Perfect reflector (all sound is reflected)
- α = 1: Perfect absorber (all sound is absorbed, none reflected)
- α = 0.5: 50% absorption, 50% reflection
- Absorption coefficient varies with frequency
- Materials absorb differently at different frequencies
Common Absorption Coefficients
- Concrete: 0.02-0.10 (very reflective)
- Carpet: 0.30-0.70 (moderate absorption)
- Acoustic Foam: 0.60-0.95 (high absorption)
- Fiberglass: 0.70-0.95 (very high absorption)
- Open Window: 1.00 (perfect absorption)
Frequently Asked Questions
What is sound absorption coefficient?
The sound absorption coefficient (α) is the ratio of absorbed sound power to incident sound power. It ranges from 0 (perfect reflection) to 1 (perfect absorption) and indicates how much sound a material absorbs.
What does α = 0.5 mean?
An absorption coefficient of 0.5 means 50% of the incident sound is absorbed and 50% is reflected. This is a moderate absorption level, typical of many acoustic materials.
Does absorption coefficient depend on frequency?
Yes, absorption coefficient varies significantly with frequency. Materials typically have different α values at different frequencies. For example, a material might absorb 0.9 at 1000 Hz but only 0.3 at 100 Hz.
What is the difference between absorption and transmission loss?
Absorption coefficient measures how much sound is absorbed (not reflected). Transmission loss measures how much sound passes through a barrier. A material can have high absorption (low reflection) but also high transmission (sound passes through).
How do I measure absorption coefficient?
Absorption coefficient is typically measured in reverberation chambers using standardized test methods (e.g., ASTM C423 or ISO 354). The material is placed in a test chamber and the change in reverberation time is measured.