There are several common acoustic problems that occur in buildings of all shapes, types and sizes. Below we've listed a glossary of common industry terms and how to identify your acoustic problem.
Echo/Long Reverberation Time
This is a common problem in rooms or buildings with many hard surfaces such as tiles, timber floors, glass, solid furniture or counter tops. These rooms or buildings often sound hollow or can have problems with speech intelligibility. Echo or Long Reverberation time can often be measured in seconds rather than fractions of seconds.
There are many different solutions that can be used to reduce echo or long reverberation times.
Sound Absorption/Noise Reduction Co-Efficient
In very simple terms, this is a measure of how well a product or material absorbs or soaks up noise. In areas prone to echo or long reverberation time problems, the goal is to increase the amount of surface areas with products or materials that offer increased levels of sound absorption. The higher the NRC of a product the more sound absorptive it is.
Impact Noise
Is often the result of noise transfer from one hard surface hitting another. As an example, shoes striking a tile or timber floor between the upper and lower level of a house or building can cause this kind of problem. It is widely accepted the most effective way of reducing impact noise is by treating the noise as close to the impact point as possible.
Airborne Noise
As its name suggests this is noise that is carried by air. Often measured using Rw / Rw + ctr. Technically, the sounds we hear are a result of pressure waves in the air. Common airborne noise problems can include a lack of privacy, noisy neighbours, loud talking, loud music, home cinema noise and equipment or machinery noise. Some of these can be resolved with sound absorption strategies, others must be addressed using decibel reduction strategies.
Decibel Reduction Strategies
This is literally the adoption of building materials that reduce the level of noise that passes through a structure. These structures may include but are not limited to walls, floors, ceilings or roofs.
Rw/STC
These are measures of noise reduction through structures. In very simple terms if a wall or ceiling has an Rw/ STC rating of Rw45, the noise passing through the wall or ceiiling has been reduced by 45 decibels.
Rw+ctr
This measure of noise is regarded as a more relevant measure of airborne noise for the modern home or building than Rw/STC. It caters to a higher standard of performance when you consider the number of causes of delivering low frequency noise in homes and buildings such as home cinemas, traffic noise and similar. The choice of materials to address low frequency noise is very important to achieving the best result.
