The Book of Acoustics

Chapter 1.0 The fundamentals of sound control

1.4 The ABCDs of sound control


When setting out to manage sound behaviour and acoustical issues in an indoor space, there are four basic approaches you can take: Absorb, Block, Cover or Diffuse.


Sound can be absorbed or captured by porous treatment materials to diminish the amount of reflection in a space. These materials can be installed on ceilings, floors, walls or be integrated in furnishings and other objects in a space. The goal is not always to add as many absorbers as possible. Rather, the optimal amount of absorbent materials used should be determined by calculating the optimal reverberation time of the specific type of space.


Sound can be blocked, or stopped from traveling, through the introduction of barriers between the sound source and the listeners in a space. A blocker can take the form of a wall, partition, a tall piece of furniture or extra layers of drywall. Blocking can involve sealing off or isolating a sound source, such as a machine, by building a separate room or isolation chamber. Appropriate ceiling material may also be necessary to block unwanted sound transmission.


Sound can be covered or masked by introducing additional sounds to a space. The aim is to make it more difficult for the brain to detect intelligible fragments of sound or conversation so that focus can be maintained on the intended activity like work tasks, for example. These active solutions are either natural or artificial in nature. Natural solutions might be, for example, an indoor water feature. Artificial solutions typically involve the use of randomly generated electrical signals that are introduced to a space via a loudspeaker.


Sound can be diffused, or scattered in different directions through the introduction of objects or materials with textured or uneven surfaces. Rather than diminish the sound, the idea is to improve its quality by reflecting and spreading it out more evenly. For example, diffusers can be used to address disturbing sound focusing or to make a dull space feel more alive. Diffusers come in different shapes and sizes, from curved panels to quadratic diffusers and custom designs. Different depths of the diffusing surface address specific frequencies.


The Book of Acoustics

This is a handbook for architects and interior designers who want to create acoustically beautiful spaces that make people feel happier, healthier and more productive.