- The fraction of sound energy that is absorbed at any surface. It has a value between 0 and 1 and varies with the frequency and angle of incidence of the sound.
- Measurement Methods
- Kundt's tube
- Using this method it is only possible to measure normal incidence absorption coefficient. A further development of this is the two microphone measurement.
- Reverberation room
- Using this method it is possible to measure random incidence absorption coefficient. A more detailed description is given within the section on reverberation time.
- There are a number of issues with the measurement of absorption. One of the main problems is mounting the absorptive material the same as the in-use condition.
- Factor describing light's ability to be absorbed per unit of path length.
See also: Absorbent Material, Absorption, Linear Absorption Coefficient, Noise Reduction Coefficient, Passive Absorber, Sound, Sound Absorption, Sound Growth.
Subjects: Noise & Vibration Optics