The developer rolled out a new version of the tool on Apr 23, 2019 and over 100K users downloaded and set up Speaker Tester. This application has ads. Many users installed the app on their Lenovo and Motorola devices.
Use the opportunity to download the .apk installation package of Speaker Tester 2.3 free of charge and take a look at users' reviews on Droid Informer. This installation package occupies 4 MB of disk space and it runs on Android devices 4.4 and above.
As users mention, you can find a poor UI and too many ads among the drawbacks of the app.