What Is Acoustic Glass?
Acoustic glass, also known as soundproof glass, or noise reduction glass is specialist glass installed in noise reduction windows that can reduce the amount of noise that is transmitted through the glass and a window (or door).
Acoustic glass is a double glazed unit that includes a pane of laminated glass. The effect of the laminate is to disrupt the soundwaves and to help dampen sound.
To understand how acoustic glass works, first we need to understand how sound travels and can pass through objects such as glass.
How Does Sound Work?
Sound is a vibration created (for example, a loud bang of two objects colliding) at a frequency that travels through molecules of air, water or any other solid object such as a brick wall until it reaches your ear. The vibration resonates on the eardrum, which translates the frequency of the sound so that you can interpret and ‘hear’ the distinct noise.
The vibrations look like waves (hence soundwave) with different frequencies having different lengths of waves. High-pitched sounds have more oscillations looking like a tighter wave and lower-frequency sounds look like a longer wave with less oscillation.
The human ear has the ability to perceive a pitch range of between 20 Hz to 20 kHz. But as it deteriorates with age, the average adult can usually detect up to 15–17 kHz, depending on their hearing ability.
The strength of the transmitted waves is called Amplitude, which reflects the intensity and physical pressure of the sound waves. This is measured in decibels (dB).
Two people speaking at home have a level of about 50 decibels.
The increase of decibels is measured using a logarithmic scale and this means that an increase of 10dB is equal to a ten-fold increase of sound. Basically, each 10dB doubles the perceived loudness of noise – 60dB would sound twice as loud as 50 dB.
Because high-pitched sounds have more oscillations, they are perceived by the eardrum as louder than a lower pitch sound at the same level of Amplitude. This is why noise from children is especially difficult to ignore, compared to an adult speaking. Lower-frequency noises also travel farther. This is why you can hear the deep thud of bass from a nightclub from miles away.
Try putting your ear to a wall when there is sound on the other side and you can hear much more clearly. This illustrates how solid objects absorb the vibration of the sound and then amplify the sound.
It’s important to understand these differences when considering how acoustic glass works and how you can improve your windows.