Exploring the accuracy of smartphone applications for measuring environmental noise

This paper reports on experimental tests undertaken to assess the capability of noise monitoring apps on smartphones to be utilised as an alternative low cost solution to traditional noise monitoring using a sound level meter. The methodology consisted of testing more than 100 smartphones in a reverberation room. White noise was utilised to test the ability of smartphones to measure noise at background, 50, 70 and 90 dB(A) and these measurements were compared with true noise levels acquired via a calibrated sound level meter. Tests were conducted on phones using the Android and iOS platforms. For each smartphone, tests were completed separately for three leading noise monitoring apps culminating in more than 1400 tests. The results suggest that apps written for the iOS platform are superior to those running on the Android platform which, in relative terms, performed rather poorly. For one of the iOS noise apps, the test results were within 1 dB(A) of the true noise level indicating the clear potential of the iPhone to be used as a low cost monitoring device in the future. The research has implications for the future use of smartphones as low cost monitoring and assessment devices for environmental noise.