What’s the difference between sound absorption and sound insulation?

Sound absorption describes whether a material absorbs or reflects the sound that hits it. Sound absorbing materials are typically used to control the reverberation of sound within a space. Sound insulation describes how much sound a material can make from one space to another. Concrete has high sound insulation (it blocks a lot of noise) but low absorption (it reflects noise back into the room). A lightweight fibreglass acoustic panel absorbs a lot of noise within a room, but isn’t suitable for blocking sound between two spaces.