Page 81 - Teaching Innovation for the 21st Century

Teaching Innovation for the 21st Century | Showcasing UJ Teaching and Learning 2021
to transform sections of audio files into a frequency domain plot which allows students to view the harmonics of sound waves (see Figure 1(b)). Audacity may have been used as the only open-source software for this activity as it also has the capability to plot the spectrogram of an audio file. However, the visualisation abilities of Sonic Visualiser are better and more user friendly than those of Audacity. Furthermore, it is good practice to expose students to more than just one software
and to present them with issues of file conversion and compatibility amongst different software. If, at some point, the developers of Sonic Visualiser will add the ability to export the raw data from a FFT, the requirement for Audacity to perform this activity may be dismissed.
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A
B
Figure 1(a): Screenshot from Sonic Visualiser showing a spectrogram of an open A string of a cello played in
arco mode. The fundamental harmonic is visible as the bright line at the bottom of the plot. (b) Screenshot from Audacity showing the raw data extracted from the audio file seen in the top panel.
Sonic Visualiser and Audacity are both licensed under the GNU GPL (v2 or later) license which allows the free distribution and modification of the software and ensures free access to everyone.
Deployment of the activity to students
Prior to the deployment of the activity, it was necessary for the instructors to know the details of the electronic devices the students were in possession of. This information was asked via a Google Form. According to the feedback provided by the class, all students had a device (a laptop or a desktop computer); roughly 90% of them used a Windows operating system, while the rest a MacOS operating system. This information was important in case special access to a computer laboratory on campus had to be organised for students to be able to do the work.