The importance of topography and building height The chosen values for the configuration can have large effects on the resulting decibel level at a certain location and it should be possible to inspect this configuration.
DATAKUSTIK CADNAA SOFTWARE
Software and the guidance that it is based on becomes increasingly complex in the attempt to model all the features of a real-world acoustic environment. This is because the calculations used cannot be included in detail and it is possible for mistakes to have been made in the process. When a noise impact assessment includes calculations from noise mapping software, it’s essential that enough information is included with the noise map to recreate these calculations again. A noise impact assessment with a noise map This is to rule out any potential error and loss of accuracy, including not using road counts to estimate the sound level of a road as a replacement of measuring the road with a sound level meter. We try to avoid using predicted sound levels when it is possible to take real-world measurements. Using noise mapping in place of a sound level meter. This is because firstly the acoustic effect of barriers is fairly well understood and secondly because the effect of the barrier is the same regardless of the level of the noise source, therefore accurate source level values are not necessary.
Noise mapping is an excellent tool for predicting the efficacy of an acoustic barrier. Using noise mapping to predict the noise reduction effect of an acoustic barrier. We believe that noise mapping is very useful but should be used only where real-world measurements are not possible, for example when predicting what height of barrier would be necessary to reduce a noise source to a certain level or to predict what impact a potential site development would create. There may be significant reflected sound paths around objects with surface absorption and ground effects reducing certain frequencies that are easily misrepresented.įor these reasons we always attempt to minimise our reliance on noise mapping and the levels calculated.
Sometimes complex building structures are reduced to simple boxes. Another example is using a line source to model a moving point source which assumes the source level is consistent throughout the entire movement. An example of this is when a source is modelled as omnidirectional, losing any directivity that is inherent.
how inaccurate these calculations might be, will increase for each instance of the model simplifying a more complex situation. Whilst the science of acoustics and how sound travels through the atmosphere is fairly well understood, it is important to remember that the calculations provided by noise mapping software are estimations that rely on accurate inputs. How accurate and reliable is noise mapping? By taking traffic information or spot measurements and combining them with aerial views it is possible to map out the effects of an existing road on a hypothetical development, or predict the screening required to bring levels below the requirements given for minimising health effects. Using formulae for predicting the creation and propagation of sound that are provided in various standards and guidance and combining this with illustrative tools and visual aids it is possible to calculate and map out decibel levels, providing useful information that can help acoustic professionals.įrom modelling sound sources using real-world measured levels that are converted into sound power levels, or using sound power levels provided by manufacturers that have been taken in laboratory environments, it's possible to model the propagation of the noise generated by these objects in various scenarios. Sound modelling has become an increasingly popular tool in acoustics, often for assessing the impact of potential developments or for predicting the effects of noise mitigation methods.
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