Visualizing acoustical beats with a smartphones

TL;DR

This paper presents a smartphone-based experimental setup for visualizing acoustical beats, demonstrating accurate measurement of beat frequencies using a simple, accessible method suitable for physics education.

Contribution

It introduces a novel, low-cost experiment using smartphones and free apps to measure sound wave superposition and beat frequencies in physics labs.

Findings

Smartphones can accurately measure acoustic beat frequencies within 1% discrepancy.

The experimental setup is simple, cost-effective, and suitable for educational purposes.

The method allows for effective visualization and analysis of sound wave interference.

Abstract

In this work, a new Physics laboratory experiment on Acoustics beats is presented. We have designed a simple experimental setup to study superposition of sound waves of slightly different frequencies (acoustic beat). The microphone of a smartphone is used to capture the sound waves emitted by two equidistant speakers from the mobile which are at the same time connected to two AC generators. The smartphone is used as a measuring instrument. By means of a simple and free AndroidTM application, the sound level (in dB) as a function of time is measured and exported to a .csv format file. Applying common graphing analysis and a fitting procedure, the frequency of the beat is obtained. The beat frequencies as obtained from the smartphone data are compared with the difference of the frequencies set at the AC generator. A very good agreement is obtained being the percentage discrepancies within 1 %.