oscilloscopes for classroom use

[Leilani Roser]

Hey folks,

I'm designing some activities and workshops for kids to build acoustic and electronically enhanced musical instruments.  I'm not much of an electrical engineer, however, so I've been collaborating with people who are and generally asking around.  I've been looking into using oscilloscopes to display waves from student-made instruments or sound recordings.

I've gotten some feedback that scopes can be a pain to get working reliably. At the same time, I've seen so many educators just casually mention that they're great for this sort of application, so I'm thinking it's a matter of using the right equipment the right way. 

Who has a favorite physical scope or interface that they love? 

What about oscilloscope apps?
If your first exposure to an oscilloscope was as an educator rather than an engineering student/professional, is there something you think I ought to know about using them?

At the moment, the most I've come up with is looking at spectral analysis apps that show you the peak frequencies coming off of a sound, or using a sound editing app to zoom way in on a recorded sound to look at the waveform. Which is all well and good and superfun. But it ain't scoping. 

[David Held]

How about using a Chladni Plate to visual sound. I've used those and also this, https://www.exploratorium.edu/snacks/vocal-visualizer, but modified it to have a speaker instead of using your mouth. I then attached the speaker to an amplier. I used my phone with an audio oscillater app to generate sound waves. 

https://makingwithheld.com/2016/05/05/visualizing-sound-part-1/

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[Lenore Horner]

I’m not sure why you’re wanting to go the oscilloscope route; I don’t see what you gain for the extra hassle.  With the oscilloscope you will need an external microphone - and maybe an amp - to convert the sound signal to a voltage signal.  If you use a physical oscilloscope, you’ll also need adapters from microphone jack to the usual bnc connector on oscilloscopes.  With the sound app you can use the built-in microphone of your device. In either case, the pressure variations of the sound wave have to be turned into voltage variations.  The oscilloscope would make your students think turn period into frequency and think about appropriate scales and maybe triggering.  Some oscilloscopes would also do spectral analysis for you (FFT).

If your goal is to let your students explore the relationships among wave shape, frequency components, and tone quality, I think you will be able to focus on that much better with a sound editing/analysis app.  

If you’re working on MacOS, I would recommend AudioXplorer even though it is no longer being updated.  On iOS, my favorite is SpectrumView, on Android I like FFTwave (for seeing the wave and the spectrum) and Spectroid (for the waterfall view and better analysis of the spectrum).  I don’t work on Windows, Linux, or Chrome devices so I don’t have any advice for them.  Probably someone else on the list does.

Lenore