Acoustics has two meanings:
(1) The science of acoustics is the study of sound, which deals with the production and transmission of sound.
(2) The acoustics of a room indicates how sound acts in a room. Acoustical engineering understand the science of acoustics and use this knowledge in designing and building structures with specific acoustics.
Good or bad acoustics depends on how well the sound can be heard. The acoustics of a room depend on how sound behaves when it hits objects. Three things that can happen:
(1) Sound reflects (bounces back from a surface) off of hard and slick materials, such as mirrors and wooden floors and furniture. (
(2) Sound is absorbed (taken in) by soft, fuzzy materials, such as carpet, curtains and padded furniture and by rough materials, such as textured walls. Sound gets trapped in these materials because most of it bounces around in the material instead of being reflected. The trapped sound energy changes to heat energy.
(3) The sound is diffused (scatters the reflected sound in many different directions) by objects with hard, smooth, uneven surfaces, such as books of different sizes on a shelf.