Can you really hear the difference?

ABX Audio enables double-blind A/B/X testing of audio clips.

You can test any audio clips on your device, in any audio format your device supports. Most versions of Android support WAV, MP3, AAC, FLAC and others.

One common use for this app is to rip a WAV to MP3s at different bit rates and ABX test each MP3 against the original WAV file to determine what is the lowest bit rate you can use that will be free of audible distortion. You can also test different encoders and results of filters at different frequencies.

You provide your own audio clips, though ABX Audio's web site has a few sample audio files to help you get started.

This app runs on any Android device (phone or tablet of any size), on any version of Android from 2.3.3 forward. It has no ads, no telemetry, doesn't use network, is free and open source, and needs storage permission only to access audio files and save its config settings.

Source code: https://github.com/MRC01/ABXAudio
Instructions & details: http://mclements.net/clementslogic/abxAudio.html