Validation of the SoundOut Room Acoustics Analyzer App for Classrooms: A New Method for Self-Assessment of Noise Levels and Reverberation Time in Schools

  • Kiri MealingsEmail author
Technical Note


Speaking and listening are the primary modes of communication in the classroom. Therefore, optimal acoustic conditions are vital for children’s learning. The aim of this study was to assess the accuracy of the SoundOut Room Acoustics Analyzer iPad app developed by the National Acoustic Laboratories against a sound level meter. Forty-eight noise level measurements were compared in laboratory settings. Forty-six unoccupied ambient noise level recordings and 46 occupied background noise level recordings were taken in classrooms, as well as 64 reverberation time measurements. Strong positive correlations were found for the noise level comparison both in the laboratory and in classrooms. With all results combined, the maximum deviation on the measurements was 3 dB and the mean deviation was 0.8 dB. A strong positive correlation was also found between the SoundOut and sound level meter reverberation times. The maximum deviation was 0.03 s, and the mean deviation was 0.01 s. These results suggest that SoundOut can be an accurate tool for educators to measure the basic acoustic conditions of their classrooms. Future research is needed to evaluate the app on other Apple devices as well as assess between-iPad variability. The accessibility of this app, which negates the need for expensive specialised equipment, has the potential to help educators become more aware of the acoustic conditions of their classrooms. The app also gives suggestions on how to improve the acoustic conditions of classrooms which could help facilitate the process of implementing improvements and doing before and after testing to assess effectiveness.


Classroom acoustics Noise level Reverberation time App 



I would like to acknowledge Jorg Buchholz and Dan Zhou, the creators of the app. I would like to thank Greg Stewart and Elizabeth Beach for their help with this study. I would also like to thank the school teachers and children for allowing me to take measurements in their classrooms. This research is funded by the Australian Government through the Department of Health.


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Copyright information

© Australian Acoustical Society 2019

Authors and Affiliations

  1. 1.National Acoustic Laboratories, Level 5 Australian Hearing HubMacquarie UniversityNorth RydeAustralia

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