A time of flight method to measure the speed of sound using a stereo sound card

TL;DR

This paper introduces an affordable, computer-based time of flight method using a stereo sound card to measure the speed of sound, suitable for educational demonstrations and laboratory experiments.

Contribution

It presents a novel, low-cost apparatus leveraging stereo sound cards for accurate speed of sound measurements in air.

Findings

Effective for quick demonstrations

Suitable for educational use

Accurate laboratory measurements

Abstract

We present an inexpensive apparatus for measuring the speed of sound, with a time of flight method, using a computer with a stereo sound board. Students measure the speed of sound by timing the delay between the arrivals of a pulse to two microphones placed at different distances from the source. It can serve as a very effective demonstration, providing a quick measurement of the speed of sound in air; we have used it with great success in Open Days in our Department. It can also be used for a full fledged laboratory determination of the speed of sound in air.