$Explaining diffraction$

The best, most cost-effective, and most supported solution for noise reduction

$Explaining diffraction$

The best, most cost-effective, and most supported solution for noise reduction

What is diffraction?

What is diffraction? It’s deflecting sound by making sound waves interact with each other. And that’s exactly what a 4Silence diffractor does: deflect troublesome sound waves from passing cars or trains upwards.

Resonance and deflection

The diffractor deflects sound because the air in the many grooves of the WHISstone, WHISwall, or WHIStop starts to resonate. Intense movement in the deep grooves deflects the traffic noise’s lower registers. The shallow grooves deflect the high notes.

This way all the troublesome sound waves are deflected, creating a quieter area next to the road.

Minimal impact on surroundings and building process

This way you can achieve large noise reductions for the long term, while barely impacting the surrounding area or the (rail)road building process.

$Explaining diffraction$

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.

$Explaining diffraction$

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.

$Explaining diffraction$

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.

$Explaining diffraction$

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.

$Explaining diffraction$

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.

Want to know more about how we use diffraction to reduce traffic noise?

More information