Interactive noise source to receiver diagram with barrier calculations
If you find this useful, you might want to check out our in-browser sound modelling tool.
This Interactive Sound Propagation Level Calculator is an approximate calculation tool and should not replace your own calculations and real life measurements.
Sound waves propagate as a sphere and follow the "inverse square law" of level reduction. A general rule is that the level reduces by 6dB per doubling of distance.
Sound waves are reduced by a barrier depending upon the frequency of the sound wave with lower frequencies less affected. The greater the path difference, the more effective the barrier is.
A general rule is that a single barrier at eye level with a source and receiver will reduce the level by approx 5dB.
ISO 9613-2:1996 only considers up to two screens. In the case of more than this, choose the two that are most effective and ignore all others.
The guidance also states that barrier attenuation is limited to 20dB for a single barrier and 25dB for two barriers. This can now be applied optionally using the calculator by deselecting "Apply limit".
Sound waves will be reflected or absorbed by the ground depending upon the frequency of the sound wave and how porous the ground is (indicated by the "Ground Factor" value G). Barrier insertion will take precedence over ground effect, the effect is not cumulative.
More information about Ground Effect can be found in the guide within our noise mapping tool
As sound waves travel through the air a small portion of the energy is converted into heat depending upon the atmospheric temperature and humidity, however the amount is only significant with high frequencies and long distances.
The original version of this calculator which used Adobe Flash can still be accessed here