If your tester's video's sound is distorted or sounds funny, it means that the tester needs to fix their audio settings on their device.
Here's what your participants will need to do to troubleshoot this issue;
Run Speech Troubleshooter;
If you're using a Windows Desktop, you can find the speech troubleshooter here; Open settings > select time & language > click "speech "> Click "get started" under "Microphone". The wizard will automatically run a troubleshoot.
Run Audio Troubleshooters
Open and run the playing audio troubleshooter by searching for this command;
%systemroot%\system32\msdt.exe -id AudioPlaybackDiagnostic
Open and run the recording audio troubleshooter by searching for this command;
%systemroot%\system32\msdt.exe -id AudioRecordingDiagnostic
Make some key changes to your mic;
Go to "settings" > Click "sound" > Under "input", select "device properties" > Select "Additional device properties" under related settings > under" Advanced" select "Studio Quality".
Restart your laptop and try the new changes by testing it out on Zoom or Microsoft Teams.
Disables Audio enhancements
You can disable audio enhancements in "Sound" located in the control panel.
Under the Playback tab, right-click the Default Device – Speakers/Headphones and select Properties > In the Properties box, switch to the Enhancements tab > select the Disable all enhancements check box.
If the method fails, select Cancel to go back to the Sound Properties box again. Now on the Playback tab, select another default device (if you have one), select the Disable all enhancements check box, and try to play audio again.
Download the latest audio driver from your device's manufacturer's’ website.
Here are more details on troubleshooting audio