Room Absorption Characteristics

Mean absorption coefficients and reverberation times for typical rooms

The table below indicates mean sound absorption coefficient  - αm - and reverberation time - Ta - for some typical rooms.

Room CharacteristicsVery SoftSoftNormalHardVery Hard
Reverberation time
- Ta -
0.2 < Ta < 0.25 0.4 < Ta < 0.5 0.9 < Ta < 1.1 1.8 < Ta < 2.2 2.5 < Ta < 4.5
Typical Room Radio and TV studio Restaurant
Lecture hall
Large church
Mean sound absorption coefficient
- αm -
0.40 0.25 0.15 0.10 0.05

The mean sound absorption coefficient should be calculated when more accurate values are needed.

The diagram below can be used to determine the sound absorption in rooms of different sizes and with different accoustic characteristics.

Sound Room Absorption

Related Topics

  • Acoustics - Room acoustics and acoustic properties - decibel A, B and C - Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation
  • Noise and Attenuation - Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems

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