THE DIFFERENT TYPES OF SOUND
Sound can take one of two forms: airborne noise, or impact noise. It is important to know the difference, as each comes with its own specific set of challenges. Products designed to reduce airborne noise will not necessarily reduce impact noise. Therefore, when designing new build homes, student accommodation or even healthcare and care home facilities, it is important to understand the difference. In doing so, those in charge of the process will be able to make well informed decisions about how to manage acoustics.
IMPACT NOISE
Impact noise occurs following a physical impact on a building, or solid material. For example, footfall and banging doors are both examples of impact sound. When impact sound occurs both sides of the building element vibrate, generating sound waves. As such, impact noises are often hardest to isolate. What’s more, in rooms with dense materials, impact vibrations tend to be stronger and travel further.
AIRBORNE NOISE
Airborne noise applies to things like TV noise, people talking and dogs barking. This form of noise travels through the air and will either reflect off building elements when it hits them, be absorbed into acoustic dense materials or travel through building structures and be radiated out to the other side. When reflected, the noise level can increase, and when absorbed or allowed to travel through structures, the volume can be reduced.
HOW IS SOUND MEASURED?
As mentioned, sound is measured in decibels (dB). Decibels denote the intensity of the sound, which relates to how much energy a sound wave contains. The human ear is capable of hearing sounds as quiet as 10 dB, but can begin to become damaged when listening to sounds of around 80 dB [2].
WHAT IS A NORMAL LEVEL OF SOUND?
The human ear is capable of hearing a great deal of sounds, but overexposure to certain levels can cause damage. Nowadays, many of us are subjected to louder environments, such as underground rail on a day-to-day basis. The following guide of relative decibel levels helps to provide some perspective: