Use this free calculator for a first rough estimate of how much a mobile noise barrier can reduce the sound level at a neighbouring receiver. Enter the source level, the distances, the barrier height and the laboratory sound reduction index of the material – the tool then estimates the level with and without a barrier.
Estimate the theoretical effect
The default values describe a typical example. Replace them with measured values or manufacturer data whenever possible. All distances and heights are given in metres.
Rough estimate only – no warranty. The result does not replace a professional noise prediction or an acoustic assessment.
Simplified setupSchematic diagram – not to scale
Direct line of sightSound path over the top edge
Changed inputs are recalculated only after you click the button.
Receiver level without noise barrier–About as loud as –
Diffraction attenuation over the top edge–
Theoretical overall effect of the noise barrier–
Receiver level with noise barrier–About as loud as –
Everyday comparisons are only a rough guide. Perception and measured levels also depend on distance, duration and frequency spectrum.
Enter your values and start the calculation.
Calculation limits: The calculator assumes one idealised point source, level ground and the sound path over the top edge of the barrier. Sound travelling around the sides, gaps, reflections, wind, ground effects, multiple machines and the actual frequency spectrum can change the result considerably. Calculated diffraction attenuation over the top edge is capped at 20 dB because higher values are generally not reliably achievable with a single mobile noise barrier under real construction-site conditions. The laboratory sound reduction index Rw is not a guaranteed on-site noise reduction value. When the second barrier is enabled, the model applies distance- and frequency-dependent double diffraction and idealised sequential sound transmission through two identical barriers. Air-gap resonance and acoustic coupling are not modelled.
How to read the result
The calculator combines two effects: sound diffracted over the top edge of the barrier and sound transmitted through the barrier material. Whichever path is weaker limits the overall effect. In practice this means that a barrier must be high enough to block the line of sight between source and receiver, and that it should stand as close as possible to the noise source.
- Height matters most: if the receiver can still see the source over the barrier, no reliable screening can be assumed.
- Low frequencies are harder: bass, transformers and generators are screened less effectively than saws or breakers.
- Gaps cost decibels: barriers should be closed, overlapping and long enough to prevent sound travelling around the sides.
The result is a theoretical estimate only and does not replace a noise prediction or an acoustic assessment by a qualified consultant.
From estimate to rental quote
If the estimate shows that a barrier can help on your site, send us the key data of your project. We check which solution fits – acoustic barrier mats for temporary fencing, compact acoustic mats, mobile noise walls 4–6 m high or a site enclosure. To measure your actual source level, you can also hire a sound level meter.