All Building materials have acoustical properties in that they will all absorb, reflect or transmit sound striking them. Conventionally speaking, acoustical treatment materials and AmCraft’s sound absorbing panels are designed and used for the purpose of absorbing sound that might otherwise be reflected. Sound absorption is defined as the incident sound that strikes a material that is not reflected back. An open window is an excellent absorber since the sounds passing through the open window are not reflected back but makes a poor sound barrier. Painted concrete block is a good sound barrier but will reflect about 97% of the incident sound striking it. Sound Absorption is frequency dependent. A material will not absorb and reflect all frequencies equally. Typically the thicker the material, the more absorption at lower frequencies.