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Mean absorption coefficients and reverberation times in typical rooms.
The table below indicates mean sound absorption coefficient - αm - and reverberation time - Ta - for some typical rooms.
Sound - Room Absorption Characteristics
|Room Characteristics||Very Soft||Soft||Normal||Hard||Very 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 |
|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.
- Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.
- Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems.
- In a room the sound or noise will reach the receiver as direct and reverberant sound.
- The sound reverberation time indicates how long it takes until the sound pressure level in a room is decreased with 60 dB.
- Room sound absorption and absorption coefficients for common materials like plaster walls, brickwork, plywood panels and more.
- Room size, absorption characteristics - and attenuation in direct sound fields.
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