Calculator Inputs
Enter panel, cavity, damping, and frequency data. The page keeps a clean single-column flow, while the input fields use a responsive three-column grid on large screens.
Formula Used
Here, ρ is panel density, t is panel thickness, F is cavity fill fraction, M is the mounting correction, γ is the air heat-capacity ratio, P0 is ambient pressure, c is the speed of sound, r is normalized resistance, and ζ is damping ratio. These equations give a practical engineering estimate rather than a laboratory certification value.
How to Use This Calculator
- Enter the panel density and thickness to determine surface mass.
- Set cavity depth to represent the backing air space.
- Add panel width and height if total panel mass matters.
- Choose a loss factor based on panel material damping.
- Enter cavity fill percentage if porous material is installed.
- Select the mounting condition to reflect support stiffness.
- Set a frequency range that covers your design target.
- Submit the form and review resonance, bandwidth, and plotted response.
- Download CSV or PDF reports for documentation and design comparison.
Example Data Table
| Case | Density (kg/m³) | Thickness (mm) | Cavity (mm) | Fill (%) | Approx. Resonance (Hz) | Approx. Peak α |
|---|---|---|---|---|---|---|
| Plywood studio panel | 600 | 12 | 100 | 30 | 69 | 0.90 |
| MDF control room panel | 750 | 9 | 75 | 20 | 83 | 0.89 |
| Gypsum low-frequency panel | 800 | 12.5 | 50 | 15 | 84 | 0.82 |
Frequently Asked Questions
1. What does a panel absorber do?
A panel absorber targets low-frequency sound by combining a vibrating panel with an enclosed air cavity. The panel moves like a mass, while the trapped air acts like a spring. Together they absorb sound most strongly around the tuned resonance.
2. Why is surface mass important?
Surface mass controls how easily the panel vibrates. Heavier panels usually tune lower, while lighter panels tune higher. This makes thickness and material density essential when aiming for a specific problematic bass range in a room.
3. How does cavity depth affect resonance?
A deeper cavity lowers the absorber resonance because the backing air spring becomes less stiff. Shallower cavities raise the tuning. Small changes in depth can noticeably shift the working frequency band, especially in bass-control applications.
4. What is the role of damping or loss factor?
Damping broadens the absorber response and reduces sharp resonance behavior. Low damping can create a narrow, strong peak. Higher damping spreads absorption across a wider range, though the highest peak may fall slightly.
5. Does porous fill inside the cavity help?
Yes. Porous fill usually increases damping and can slightly alter effective cavity behavior. It often smooths the response and widens useful bandwidth. In practice, it helps reduce extreme narrowness around the tuned resonance.
6. Is the calculated absorption coefficient exact?
No. This tool provides an engineering estimate based on a simplified normal-incidence model. Real results depend on construction details, leakage, mounting, air gaps, panel stiffness, finish materials, and measurement method.
7. Why compare resonance and quarter-wave frequency?
The resonant frequency shows where the panel-mass system is tuned. The quarter-wave frequency offers another acoustic reference for the cavity. Comparing both helps you understand whether the design behaves as an absorber, a cavity effect, or both.
8. When should I use a flexible mounting condition?
Use a flexible option when the support frame adds compliance or the mounting is less rigid than a fully fixed edge. This can shift tuning and damping. It is helpful for practical site estimates before detailed testing.