Reflection is when a sound wave hits an object or surface such as a wall and reflects or rebounds. Reflection often occurs in areas where there are smooth and hard materials, and can lead to sound amplification, echoes or reverberation. Too much reflection can make a room noisy and irritating.
Diffusion of sound occurs when the texture and irregularities of an object or material are comparable to the wavelength of the sound. The nature of the surface structure determines how the sound spreads. Too much diffusion makes it difficult to determine where the sound is coming from.
Sound can be absorbed when it encounters an object or material. It is then converted into heat energy in the object or material that absorbs it. The amount of energy absorbed or allowed through depends on the thickness and nature of the material. Too little absorption causes sound to reflect.