Absorption materials are used to control sound within a space. Acoustically absorptive materials are typically rated with an NRC number. Some materials may also be rated with a CAC number (usually ceiling tiles) and yet others may be rated in Sabines.

Absorption panels can be used to control harsh reflections, reduce reverberation time, or eliminate echo. Absorption panels can also be used to reduce the propagation of sound in otherwise open areas (i.e., down a long hallway).

Acoustic absorption panels come in many shapes, sizes, and materials. Below are some examples: