1 To comply with Department of Defense changes to common access cards, and to comply with Homeland Security Presidential Directive 12, the Fort Knox One Stop In-processing Center has recently started implementing changes to the CAC issuing process.
acoustics - the study of the physical properties of sound. acoustic radiation pressure - (acoustics) the pressure exerted on a surface normal to the direction of propagation of a sound wave. physical science, physics - the physical properties, phenomena, and laws of something; he studied the physics of radiation. harmonics - the study of musical sound.
Airborne noises are the noises from outside (traffic, voices, etc.) and also include sounds from the TV, music and other noise producers inside. Impact noises include footsteps and vibrations from large appliances such as your washer and dryer. Insulation reduces both airborne and impact noises.