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  Home   >   Optics & Wave   >   Experiment    

Sound Beats

1. Introduction

When two sound waves with different but close frequencies interfere with each other, what is heard is a sound whose frequency is the average of the two original frequencies. This sound varies in intensity and the variations in intensity have a frequency that is equal to the difference between the two original frequencies.

If the original waves are:

Where f1 and f2 are the frequencies, then the composite wave will be of the form:

In this experiment we explore the form of the composite wave by viewing the readings of a microphone and by looking at the Fourier transform of these readings.

2. Equipment List
Datalogger interface connected to a PC
Two tuning forks mounted on sounding boxes (frequencies: 440Hz, 435Hz)
A rubber hammer to sound the forks
Sound sensor

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  Sound Beats















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