Inside be quiet!

13.02.2019
What is a noise-dampening mat? How is it built? And what exactly is its purpose?

There are many ways to turn a loud PC into a silent one - like using silence-optimized fans, SSDs instead of HDDs or decoupled mountings for case fans or HDD cages. An important part of a really quiet PC doesn't appear on too many radars as it's really inconspicuous and mostly taken for granted: the noise-dampening mat. But what does it do exactly?

Lots of smaller noise sources add up, and in the end a loud PC is nothing more that the result of neglected soundproofing. But the focussed dampening of a PC can make a difference of several decibels! The mat's first and foremost duty is to absorb certain frequencies so that they can't leave the case. These noises, whose range usually lies between 1.500 and 5.000 Hz, can originate in PSU coils or cheap fan bearings, for example. How effectively they are being dampened depends on the mat's composition.
In earlier days dampening mats mostly consisted of simple foam material shaped in an eggshell style - which was better than nothing but left a lot to be desired. These days they consist of several layers of bituminized board and highly densed foam which take care of a multitude of potential noises, as well as a finishing layer of fleece with very fine burls which break sound waves thousandfold within the case. By default these mats are between 5 and 10 mm thick. Finding the right size is quite a delicate operation: It mustn't be too thin as this would have hardly any effect. But it also cannot be too thick as then the mat would be literally in the way of airflow, components and cables - which would have a direct and negative impact on the inside temperature, which then would make the fans spin faster, hence make them louder and sabotage the whole operation.
Also large and thin surfaces like case side panels can act as membranes, transporting and intensifying noises from inside. A dampening mat solidifies this surface, minimizing its vibration potential. Vibrations are usually the result of moving parts within the case, like rotating fans. Of course high-grade bearings and aerodynamic fan blades reduce these to a minimum, but they cannot be avoided completely. Other components with moving parts like hard drives also contribute to that, which can be reduced by utilizing rubber mountings on the HDD cages which absorb most of the vibrations.

 

In the early noughties be quiet! was one of the first producers of specialized noise-dampening mats. Back then our mats were quite colorful, by now we've resorted to anthracite which is more pleasing in pretty much every conceivable way. We have several noise-absorber kits in store, optimized for mid-size and full-size towers. A carefully selected set of noise-dampening mats should be part of every modern PC, just like an efficient power supply and quiet fans. They are no panacea, though - merely putting a mat into a loud PC does not magically turn it into a whispering miracle. It's part of a full silence concept, the cherry on top, which makes the difference between "it's fine" and "it's really silent". All of our cases are fully equipped with noise-dampening mats of course, with high-grade versions in the case of our silene-optimized ones.