what is sound

Understanding Soundproofing: What is sound?

What is sound?

At its most basic level, sound is a very small and very rapid fluctuation in air pressure above and below atmospheric pressure. All sounds – an HVAC system, a vibrating cell phone on a desk, road traffic – operate using this principle. The ear is very sensitive to sound sources and the range of pressure vibration from the weakest to the loudest sound heard is extremely large.

The ear doesn’t experience sound in a linear fashion. Instead, it uses a logarithmic scale with a measure of energy in decibels (dB). To the ear, a sound heard at 60dB only needs to decrease to 50dB to experience this sound as being half as loud. Furthermore, a sound going from 60dB to 40dB (i.e. a busy street to a quiet library), would be experienced as an even more dramatic change. The potential for a sound to damage our hearing is proportional to its intensity, not its loudness as shown in the table below.

what is sound

Facts about sound

  • Acoustical engineers use decibels (dB) to measure sound or quantify sound loudness.
  • The energy in the loudest sounds typically heard is one million times that in the weakest sounds audible.
  • The ear is a tremendously sensitive organ; the range of pressure variation from the weakest to loudest sounds heard is extremely large.
  • To make a sound twice as loud requires 10 times as much power. Inversely, to make it half as loud, 90 percent of the sound must be eliminated.
  • The decibel logarithmic scale measuring sound shows that while a 3 dB change leads to a barely noticeable perceived difference to the human ear, a 20 dB swing is a very dramatic change.
 

How is sound measured?

what is sound

Acoustical engineers use decibels to quantify sound loudness, but when it comes to acoustics design in buildings, that measure is just one way of evaluating its performance.

There are two primary metrics used in noise measurement for evaluating the acoustic performance in a building’s acoustical performance – acoustical absorption and sound transmission loss.

Acoustical absorption is the ability of a material to absorb rather than reflect sound (think about the difference between jumping onto a trampoline vs into a pile of pillows). Sound transmission loss refers to a material’s ability to reduce sound transfer from one space to another (i.e. blocking noise or sound between rooms). When you’re trying to find a solution to meet good architectural acoustics requirements for your next project, it is important to know the difference between the two.

When referring to sound absorption, you should look for products that absorb reverberation and echoes in a room. If you want a product that will stop or block a sound, you’ll need a heavier, denser material. Materials with high sound absorption are not great for stopping sound transmission. For example, concrete is great for sound transmission loss, but not great for sound absorption.

For all of your soundproofing needs, contact Acoustica Projects.

Phone : 1300 722 825 or 02 9550 2900
Email : enquiries@acousticaprojects.com.au
Website : https://www.acousticaprojects.com.au/