Add point sources, screening barriers, buildings and decibel receiver points with detailed frequency information. See the sound paths and how these are affecting the levels. Interact with your model, modifying positions and parameters and see the calculation results instantly.
Learn through experimentation how the calculations of ISO 9613 parts 1 and 2 are implemented and how they affect predicted levels. Built into your browser, your model is stored in the location bar making it easy to save and share your interactive models with other people.
Start noise mapping - works in any modern web browser
The tool is still in development and we welcome your feedback
You can also access the tool by visiting dbmap.co.uk
A decibel sound level calculator with interactive diagram. For calculating a single source of noise considering sound attenuation due to:
Using ISO 9613 methods of calculation.
Use the calculator - requires flash
Original noise calculator - combine up to 3 independent point sources at different distances and durations.
Sound levels (decibels) are logarithmic so they do not scale the same as other units of measurement. You will need a better understanding of this to perform mathematical calculations yourself, but some useful examples:
Sound energy propagates outwards in a sphere and therefore reduces in energy based on the "inverse square law".
This is easily understood as a reduction in 6dB per double of distance. So the reduction from 1m to 2m distance is the same as from 100m to 200m distance.
There are many aspects to consider when modelling sound level both regarding the laws of physics and environmental effects on the sound. Some of the things to consider are:
It is a international standard that describes a method for calculating the attenuation of sound during propagation outdoors in order to predict the levels of environmental noise at a distance from a variety of sources. The method predicts the equivalent continuous A-weighted sound pressure level (as described in ISO 1996) under meteorological conditions.
The accuracy is always going to be limited to the details of the model, which will never quite match the real world conditions perfectly.
There is more information about accuracy in the noise mapping tool guide.
The human ear doesn't respond to all frequencies equally. For example: a sound at 1kHz will appear much louder than a sound of equal energy at 50Hz. A-weighting is a frequency-based adjustment to the decibel level to account for this variance in audibility. It is common to use a-weighted levels dB(A) when referring to noise impact as .
When you see a decibel level for a source of noise it is usually accompanied by a distance from the source, this is a sound pressure level and indicates how much sound energy is present at this distance. e.g. A compression unit is 70dB at 1m distance or 50dB at 10m.
The sound power level does not contain distance information and instead represents the total acoustic energy of the source of noise, e.g. The same compression unit has a sound power of 81dB. Using this figure we can calculate the sound pressure level at any distance. We can also estimate the sound power level by using a pressure level with the distance from the source. All of our calculators provide methods for doing this.
We are considering adding a calculator for this. If you think it would be beneficial please let us know.