WHIS®top New: Now calculate your own noise reduction here using the WHIStools WHIS®wall
  • Reducing noise while preserving views
  • More cost-effective
  • More durable
  • Easy to install
1 What is diffraction? Diffraction is the scientific principle that sound waves can deflect when colliding with a diffracting element. Here’s how it works in the case of the WHIS®stone. 2 Traffic noise = rolling noise Traffic noise is caused by rolling noise, the biggest sound source above 40 km/h. These sound waves roll off the road horizontally. 3 WHIS®stone – grooves capture noise The horizontal sound wave meets the WHIS®stone: an element with grooves of varying depths. These grooves cause resonance. 4 Noise reduction by pushing soundwaves up This leads to a resistance in the air, hindering the horizontal sound waves. Like water, sound looks for the path of least resistance. So the horizontal sound waves ‘dodge’ the WHIS©stone’s waves by deflecting upwards and continuing in that direction. 5 A quieter area alongside the road This happens at an angle of about 25 degrees, creating a quieter area behind the WHIS©stone. The same applies to the WHIS©wall and WHIS©top.

What we stand for:

Lower
costs

Installing the products is quick and easy. No (extra) foundation is needed, so the building process isn’t slowed down.

Environmentally
friendly

All our products benefit (people in) the environment: views remain almost entirely intact in most cases, for both (train) travelers and residents.

A deal’s a deal

We’re a practical and down-to-earth group of people: we do what we say and we say what we do.

Proven
noise reduction

As a spin-off of Twente University, we attach a great deal of value to proving the effectiveness of our products through science.

Sustainable
solutions

Unlike solutions like silent asphalt, our products remain fully effective throughout their entire life span (>30 years

Wide-ranging expertise

The 4Silence team consists of a combination of (rail)road construction experts and acoustical engineers. Together we’ve created a solution that not only works very well, but also is easy to apply.

“No one should suffer from the growing demand for mobility and the (increasing) traffic noise that comes with it.”

Ysbrand Wijnant, inventor of the diffractor

Want to see how diffraction works?
Watch the video