Measuring and analyzing sound using phone microphone and free software

In Fall 2022 acoustics class, the students developed class projects using their smart phones to measure sound. In a laboratory exercise, the phones were calibrated against a standard microphone. A microphone circuit was bread boarded and calibrated to demonstrate the inner workings of electret micro...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2023-03, Vol.153 (3_supplement), p.A360-A360
Main Author: Wright, Andrew
Format: Article
Language:English
Online Access:Get full text
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Summary:In Fall 2022 acoustics class, the students developed class projects using their smart phones to measure sound. In a laboratory exercise, the phones were calibrated against a standard microphone. A microphone circuit was bread boarded and calibrated to demonstrate the inner workings of electret microphone technology. Students developed projects around the measurement of sound, including measuring striking a cymbal, analyzing piano chords, analyzing guitar chords, characterizing reverberation time in a warehouse, and determining the amplification from a 3D printed human ear and bat ear. The sound files from the phone were edited to isolate the relevant sound and converted to WAV files using Garageband software. The WAV files were imported into Python for post-processing, such as windowing, filtering, and FFT. Most projects used a waterfall plot to demonstrate some time-frequency analysis. The ease with which the students mastered sound measurement and processing led to unexpectedly mature projects. The low cost of the equipment makes this approach a widely deployable educational paradigm.
ISSN:0001-4966
1520-8524
DOI:10.1121/10.0019162