In concert hall acoustics, it's the opposite of reflection; the Sabin is a unit of it
Metric sabin: [L2]---the unit of measure of sound absorption in 
the... [DOC] [TLE] Physics 4830 Course Notes - University of Colorado Boulder [PAR] Last time: Reflection, Superposition, Acoustical Intimacy ... is important, however, 
it is often over-emphasized and its importance over rated.