Room Acoustic Input Form
Example Data Table
| Parameter | Example Value | Unit | Purpose |
|---|---|---|---|
| Room Length | 6.2 | m | Defines axial modes along the longest axis. |
| Room Width | 4.3 | m | Influences side wall modal spacing. |
| Room Height | 2.8 | m | Determines vertical standing wave positions. |
| Target RT60 | 0.35 | s | Sets desired decay time for treatment planning. |
| Ceiling Absorption | 0.55 | ratio | Represents acoustic cloud or treated surface performance. |
| Amplifier Power | 120 | W | Estimates playback level at the seat. |
Formula Used
Room volume: V = L × W × H
Surface absorption: A = Σ(Surface Area × Absorption Coefficient)
Sabine reverberation: RT60 = 0.161 × V / A
Axial room mode: f = n × c / (2 × d)
Schroeder frequency: Fs = 2000 × √(RT60 / V)
SPL at one meter: SPL = Sensitivity + 10 × log10(Power)
SPL at listening position: Seat SPL = SPL at 1 m − 20 × log10(distance)
These formulas provide a practical engineering estimate for acoustic decay, resonance clustering, and playback strength inside a rectangular listening room.
How to Use This Calculator
- Enter room length, width, and height in meters.
- Set a target RT60 based on studio, theater, or hi-fi goals.
- Input temperature and humidity for a realistic sound speed estimate.
- Provide listening distance, speaker sensitivity, and amplifier power.
- Enter absorption coefficients for each major room surface.
- Submit the form to view RT60, room modes, SPL, and treatment needs.
- Use the CSV or PDF buttons to export the calculated summary.
Frequently Asked Questions
1. What does this room EQ calculator estimate?
It estimates room volume, surface absorption, reverberation time, axial room modes, Schroeder frequency, and approximate listening level. These outputs help guide treatment decisions in rectangular rooms.
2. Is this a replacement for measurement microphones?
No. It is a planning and screening tool. Real measurements with calibrated microphones and analysis software remain essential for confirming peaks, nulls, and decay behavior.
3. Why are only axial modes shown?
Axial modes are usually the strongest and easiest to interpret first. Tangential and oblique modes matter too, but axial frequencies provide a fast, useful starting point.
4. What RT60 should I target?
Small control rooms often aim around 0.2 to 0.4 seconds. Home theaters and listening rooms may vary depending on size, furnishings, and intended sound character.
5. How should I choose absorption coefficients?
Use manufacturer data or published acoustic tables for the relevant frequency range. If exact values are unavailable, choose realistic averages for broad planning work.
6. Why does temperature affect results?
Temperature changes the speed of sound, which shifts calculated room mode frequencies slightly. Humidity also contributes a smaller adjustment in practical indoor conditions.
7. Can this calculator help with speaker placement?
Yes, indirectly. The mode list, room ratios, and distance-based SPL estimate can inform placement decisions, though boundary interference and reflections still need separate evaluation.
8. What does extra absorption needed mean?
It is the difference between current equivalent absorption and the amount required to reach the chosen RT60 target. It helps size added panels or treatment coverage.