In the context of this short essay on "controlling noise", the enclosed work space could be an open plan office, a work-shop, a refectory or an exhibition area. The term "noise" can be defined as 'any audible disturbance that interferes with normal conversation in the area of immediate interest'.

Controlling noise in any environment requires some knowledge of how sound is propagated and the effect that various materials have on sound waves. After being given a few basic facts, most problems can be alleviated or even solved by using "common sense".

Sound waves tend to expand in all directions away from the point of origin.

The energy content of a sound wave tends decreases with distance.

Sound waves are absorbed by most 'soft' materials.

Sound waves are reflected by any 'hard' material.

Sound waves can be "bent" around large objects.

In practical terminology; a room with a lot of soft furnishings, floor and wall coverings will tend to absorb sound and produce a reasonably well controlled environment in which sound energy decays quickly; a room with hard walls (or a lot of glass), a polished floor and no upholstered furniture will reflect sound from one surface to another such that sound energy tends to increase and decays very slowly.

If a room is relatively absorbent, noise control is comparatively easy. If a room is highly reflective, noise control is very difficult or impossible.

In short, if we are to successfully control unwanted noise in any enclosed space, we must get the acoustic environment 'on our side'. We need to obey a few basic rules:

We must "treat" all large surface areas with acoustically absorbent material.

We can segregate areas of the same room by using low cost acoustic baffles (free standing or fixed absorbent panels).

Any sound reinforcement equipment must be designed to put the minimum amount of acoustic energy into the space. This often requires specialist knowledge of loudspeakers so that sound can be 'focused' in the required area.