The Smartphone as a Sound Level Meter: Visualizing Acoustical Beats

Abstract

[EN] Acoustics is a topic in first year Physics courses for engineering students. In this respect, we present in this work a simple experiment to study acoustic beat phenomenon. The superposition of sound waves of slightly different frequencies is captured with the microphone of a smartphone which is placed equidistantly from two speakers which are connected at the same time to AC generators. The smartphone is used here as a measuring instrument. Data registered from the sound level versus time were collected and exported to a «.csv» file for further analysis by means of a free Android application. Based on these data and applying a simple graphing analysis the frequency of the beat was determined and compared with the frequency difference set at the AC generators. Percentage discrepancies within 1% were obtained. This indicates the efficacy of the method used.The authors would like to thank the Institute of Education Sciences of the Universitat Politècnica de València (Spain), for the support to the research groups on teaching innovation MoMa and e-MACAFI and for supporting the Project PIME/2015/B18 which gave rise to this workSalinas Marín, I.; Gimenez Valentin, MH.; Castro-Palacio, J.; Gómez-Tejedor, J.; Monsoriu Serra, JA. (2017). The Smartphone as a Sound Level Meter: Visualizing Acoustical Beats. Tecnica Industrial. 318:34-38. https://doi.org/10.23800/9948S343831