Room attenuation in a direct sound field as function of room size and room sound absorption characteristics:
- 1 ft2 = 0.0929 m2
The diagram is based on a listener within 5 ft (1.5 m) from the source.
Typical Rooms and their Absorption Characteristics
- Hard - bath rooms, large churches, gymnasiums, factories
- Average - private homes, concert halls, restaurants, offices, conference rooms, hotel rooms, school rooms, hospitals, libraries, churches, reception rooms
- Soft - radio and TV studios, theaters
Example - Sound Attenuation in an "Average" Room
The sound attenuation in an "average" room with surface 100 m2 (1076 ft2) can be estimated from the diagram above to be approximately
Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.
In a room the sound or noise will reach the receiver as direct and reverberant sound.
The speed and attenuation of sound in moist air varies with sound frequency and air humidity.
The attenuation in a room depends on the location of the sound source and the receiver - and the room constant.
The sound reverberation time indicates how long it takes until the sound pressure level in a room is decreased with 60 dB.
Mean absorption coefficients and reverberation times in typical rooms.
Room sound absorption and absorption coefficients for common materials like plaster walls, brickwork, plywood panels and more.
Sound Pressure is the force of sound on a surface perpendicular to the propagation of sound.