Error bounds, uncertainties and confidence limits of outdoor sound propagation

Nicholas Sylvestre-Williams, Ramani Ramakrishnan


Determination of uncertainties of the predicted noise levels associated with the standard environmental variables that were encountered while taking measurements, such as temperature, wind speeds, and relative humidity was investigated. The investigation included both the prediction of far-field noise levels from a known sources of sound, and the measurement of noise levels. Measurements were compared to the predicted sound level calculated via the ISO 9613 standards, using the software program CADNA/A. The environmental recording equipment were set up next to the far-field microphone, and the air temperature and humidity was recorded every 1 minutes. Result of the testing shows a good correlation, when the distance is 100 meters, and for distance of approximately 300 meters there are deviations between the predicted and the measured values.


Atmospheric humidity; Computer software; Error analysis; Microphones; Standards; Air temperature; Far-field noise levels

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