Absorption coefficients reduce reflected intensity by their proportion

Evidence

The amount of sound energy available for contribution to the reverberant field is also a function of the absorption, because if there is a large amount of absorption, there will be less direct sound reflected off a surface to contribute to the reverberant field-remember that before the first reflection, the sound is direct sound. The amount of sound energy available to contribute to the reverberant field is therefore proportional to the residual energy left after the first reflection, Reverberant level is that which allows input to equal output FIGURE 6. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1763 (#corroborates, via linked claim)

The decay of the reverberant field level: When a tone in the space stops, or after a transient, the reverberant sound level will not reduce immediately but will instead decay at a rate determined by the amount of sound energy that is absorbed at each reflection. Thus in spaces with a small amount of absorption, the reverberant field will take longer to decay. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1743 (#corroborates, via linked claim)

Categorization

  • XREF: connects to: The random-incidence absorption coefficient is not a percentage and exceeds 1.0; Surface absorption weakens early reflections below inverse-square-law predictions; Higher absorption reduces the first-reflection energy that feeds the reverberant field — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1763 (+1 more)

Broader Connections