Different types of acoustic materials that can be used for noise control. It describes sound absorbers, diffusers, barriers, and reflectors. Sound absorbers are porous materials used to eliminate sound reflections and reduce reverberation. I.e. Echo PET, Wood wool acoustic panel, Acoustic foam panels and fabric wrapped panels made of materials like fiberglass, foam, or fabric. Acoustic panel Sound diffusers help disperse sound uniformly. Noise and sound barrier made of materials like MLV, concrete, wood or metal are used to block transmission of sound waves. Sound reflectors are used to redirect sound waves.