Sound Absorbing Materials

Abstract

Materials for noise and vibration control may be broadly classified into those applicable for treatment of the source, for reduction along the noise path and for receiver treatment. Since one is concerned with a dynamic energy source, a multitude of paths, and a human receiver that is highly mobile and sensitive, material types are innumerable. Complicating matters further, some materials are used extensively at all three locations in the noise equation, namely the source, path and receiver. For this reason we have chosen to categorize material types as follows:

• Absorbing Materials — those that dissipate or convert sound energy on impact.

• Barrier Materials — those that block sound waves.

• Vibration isolation/damping materials — those that reduce radiated sound.

• Silencers, passive and active — those that suppress sounds.