How to use an oscilloscope for audio

An oscilloscope is an essential piece of equipment for anyone who wants to work with audio.

This allows you to see the waveforms, which is essential for diagnosing and troubleshooting audio problems.

In this blog post, we will discuss how to use an oscilloscope for audio.

What does an oscilloscope do?

An oscilloscope is an electrical instrument used in various fields to display an electrical signal. An oscilloscope shows the waveform of an electrical signal, so it is used to view audio signals.

The instrument converts electrical signals into waves and displays them on a graphical screen that contains an X-axis and a Y-axis. 

The oscilloscope separates the sound into intensity/amplitude and changes the intensity over time.

While the Y-axis shows the intensity of the sound, the change in intensity over time is shown on the X-axis. To clarify, the X-axis is the horizontal axis and the Y-axis is the vertical axis. 

How to connect an oscilloscope to audio?

Music is an example of sound, meaning it can be measured with an oscilloscope.

To measure music or sound in general, you need an oscilloscope, an MP3 player or radio as your music source, a mini phone cable, headphones, and a Y-adapter.

The purpose of headphones is to listen to music the way you measure it, and headphones are a good alternative. 

The first step to connecting and measuring audio with an oscilloscope is to turn on the instrument. Follow this by setting the input link to AC (alternating current). Complete the adjustment by adjusting the vertical input control to one volt per division and the horizontal speed to one millisecond per division. 

Depending on the desired frequency of the waves, you can change the sweep speed at any time.

In addition, you can adjust the oscilloscope's vertical input to increase or decrease the waveforms. Your music player's volume control is another way to adjust the size of the waves.

It's worth noting that the "Y" adapter gives you two ports to connect your headphones and mini phone cable at the same time. Remember that most music players only have one headphone jack. 

Now plug the Y-adapter into your music player's headphone port and connect your headphones to one port and the mini phone cable to the other port. Play music on your music player or car audio system, or tune the radio to the desired station to have audio output. Put on your headphones to listen to music.

Connecting an oscilloscope 

Connecting an oscilloscope can be a little tricky. A basic oscilloscope guide can help.

Your mini phone cable only has one loose end, but you want to connect two of your oscilloscope cables: the input probe and the ground clamp. 

If you check the unconnected end of your mini telephone cable, it is divided into three sections with insulating rings, usually black.

Attach the oscilloscope's input probe to the tip of the telephone mini cable, and the oscilloscope ground to the third section, leaving the middle section unused.

The sound waveform of your sound should now be displayed on the screen of your oscilloscope with amplitude on the vertical axis and change in amplitude over time on the horizontal axis.

Again, you can view waveforms at different frequencies by adjusting the scope's sweep. 

Can an oscilloscope measure music?

One of the purposes of an oscilloscope is to measure sound waves. Because music is an example of sound, it can be measured with an oscilloscope. 

What is an oscilloscope used for in audio?

We measure the sound with an oscilloscope to study the behavior of the sound. When you speak into the microphone, the microphone converts the sound into an electrical signal.

The oscilloscope displays an electrical signal according to its amplitude and frequency.

The pitch of the sound depends on how close the waves are to each other, that is, the closer the waves, the higher the pitch.

How to connect an oscilloscope to an amplifier?

One of the common functions of an oscilloscope is troubleshooting an amplifier. That being said, your oscilloscope is a great tool for troubleshooting your amplifier if you have poor audio output.

You can study the state of the sound from the amplifier by watching the waveform on the oscilloscope screen. Generally, the smoother the wave, the better the sound.

Start by removing the rear and top panels of the amplifier. Loosen the screws with a screwdriver to expose the circuit board and chassis ground needed for troubleshooting.

It would be better if a sine wave generator was connected to the output of the amplifier, although this depends on the test.

However, regardless of the type of test, connecting a sine waveform generator to an amplifier will not damage either the amplifier or the oscilloscope.

It's best to plug in the generator rather than plugging and unplugging it frequently.  

Troubleshooting the amplifier requires that it operate as it would in normal use.

While this may mean connecting a speaker to output sound, avoiding this is bad practice. Connecting the speaker may damage it and even damage your hearing.

Since the current from the amplifier has to go somewhere, it is best to connect only the red cable of the electronic load to the amplifier. In this case, the electronic load absorbs the reduced power while the amplifier is operating normally.

Connect the oscilloscope by attaching a ground cable to the amplifier chassis and turning on the function generator. Set the oscilloscope to direct current (DC) coupling and set other controls to zero. 

It is worth noting that the purpose of connecting the ground cable to chassis ground is to prevent electrical shock during the procedure. 

Begin troubleshooting the amplifier by holding the oscilloscope probe to the part of the amplifier you want to test. You can adjust the view on the oscilloscope using the voltage and time scales.

For this test, the X-axis represents time and the Y-axis represents voltage, giving a curve of power dissipation as it passes through the amplifier. 

Look for faulty parts of the amplifier by looking on the oscilloscope screen for parts with uneven waveforms with intermittent peaks. A healthy component will produce a regular undulating waveform. 

However, testing the power supply requires a slight change in settings. Switch the oscilloscope to AC-coupled to check the power supply. A waveform that doesn't look like ripple when you press the oscilloscope probe against the output transformer could indicate a problem with the primary winding.

Conclusion

So there you have it - how to use an oscilloscope for sound. By following the simple steps outlined in this guide, you can easily start recording and analyzing your own music and sounds. Happy using the oscilloscope!