Use: Absorbers are used to reduce noise reflection and to dissipate noise energy.
Physical Properties: Absorbers are porous, fibrous and sometimes covered with protective membranes. Noise enters the absorber and is partly dissipated (absorbed) within the material: some is transmitted and some is reflected.
Absorber performance is expressed as a decimal value. A perfect absorber is rated at 1.00. The higher the decimal value the more effective the absorber will be.
Effectiveness is expressed as NRC (Noise Reduction Coefficient).
NRC is the percentage of acoustical energy absorbed calculated as an average of laboratory test data at several frequencies.
|1/8" pile carpet||.15|
|5/16" pile carpet and foam||.35|
|Plaster, smooth finish||.05|
|Plywood paneling, 1/4" thick||.10|
|Water surface (as in swimming pool)||.00|
|1" thick fiberglass curtain||.70|
|3" thick "SONEX" wedge foam||.86|
|4" thick smooth surface foam||.89|
|4" thick metal panel||.95|