Increasing the Rw by one means its more effective and reduces the noise level by approximately 1dB. This figure rates the effectiveness of a soundproofing material. The Rw is the weighted sound reduction weighted Index figure. The most common unit of performance that all companies quote is the performance of a system quoted in decibels this will be in its most basic form the Rw figure. A 1% gap in the surface you are trying to insulate will result in a 10% loss in performance. Remember, you must treat soundproofing like waterproofing, aiming to block every tiny crack and hole.
The aim of soundproofing is to try and bring the sound within a room back to what we would call "normal ambient sound" which is around 30-40dB. This is physically impossible! They will be talking about the overall performance of their product plus the wall it is stuck to which is already there! Be warned when buying soundproofing materials and solutions: many companies will boast 50dB in addition to their product's performance. And a 20dB improvement will give another 50% of 50% on top, ie. So, for example, a 10dB improvement in your wall soundproofing, you will hear roughly 50% less sound coming through. Sadly, ear damage is caused by intensity not perception.Īs a rough rule of thumb, each 10dB increment increases the intensity by ten times, and sounds twice as loud. Unfortunately, the scale is not linear, so a sound that is 80dB is actually ten times as intense as one that is 70db! And to complicate matters further, the human ear will not actually perceive this as a ten fold increase, instead it will sound twice as loud roughly. The numbers can feel meaningless without a little context - you can see below what decibels (dB) means roughly:
Perhaps the most confusing thing about soundproofing is the scale that is used to measure noise. This scale is used particularly in applications where sound travels in water.Decibels are a key metric in the world of soundproofing so continue reading to understand what they are, how they are measured and why it is important to understand how they work. It should be noted at this point that there is another decibel scale in use, called the sound pressure level, based on the ratio of the pressure amplitude to a reference pressure. For example, a 56.0 dB sound is twice as intense as a 53.0 dB sound, a 97.0 dB sound is half as intense as a 100 dB sound, and so on. In equation form, intensity I is I=\frac\\ is given (and not the actual intensities), this result is true for any intensities that differ by a factor of two. Power is the rate at which energy is transferred by the wave. Intensity is defined to be the power per unit area carried by a wave. The relevant physical quantity is sound intensity, a concept that is valid for all sounds whether or not they are in the audible range. High noise exposure is hazardous to hearing, and it is common for musicians to have hearing losses that are sufficiently severe that they interfere with the musicians’ abilities to perform. In cartoons depicting a screaming person (or an animal making a loud noise), the cartoonist often shows an open mouth with a vibrating uvula, the hanging tissue at the back of the mouth, to suggest a loud sound coming from the throat Figure 2. We are all very familiar with the loudness of sounds and aware that they are related to how energetically the source is vibrating. But when a passing motorist has his stereo turned up, you cannot even hear what the person next to you in your car is saying. After settling into bed, you may hear your blood pulsing through your ears. In a quiet forest, you can sometimes hear a single leaf fall to the ground. Noise on crowded roadways like this one in Delhi makes it hard to hear others unless they shout.