Room Absorption Sound
Reference data and engineering information about room absorption sound for acoustics applications.
Overview
Engineering reference data for Room Absorption Sound in acoustics.
Key Formulas
Speed of Sound
Speed of sound in an ideal gas.
Sound Level
Decibel level.
Wavelength
Wavelength = speed / frequency.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Speed of sound | m/s | |
| Sound level | dB | |
| Wavelength | m | |
| Frequency | Hz |
Room Absorption Characteristics Table
The following table summarizes room characteristics, typical reverberation time ranges, and mean sound absorption coefficients for different room types.
Room Characteristic | Reverberation Time Range (Ta) | Typical Rooms | Mean Absorption Coefficient (αm)(-) |
|---|---|---|---|
| Very Soft | 0.2 < Ta < 0.25 | Radio & TV studio | 0.4 |
| Soft | 0.4 < Ta < 0.5 | Restaurant Theater Lecture hall | 0.25 |
| Normal | 0.9 < Ta < 1.1 | Office Library Flat | 0.15 |
| Hard | 1.8 < Ta < 2.2 | Hospital Church | 0.1 |
| Very Hard | 2.5 < Ta < 4.5 | Large church Factory | 0.05 |
Source: engineeringtoolbox.com
Mean Sound Absorption Coefficient Calculation
For more accurate values, the mean sound absorption coefficient () should be calculated using the weighted average of individual surface absorption coefficients:
Where:
- is the sound absorption coefficient for surface ,
- is the area of surface ,
- is the total number of surfaces.
This coefficient directly influences reverberation time (), with higher leading to shorter reverberation times and a softer acoustic environment. Use the table above for quick reference or the formula for detailed room analysis.