A free program for Android, by Leafgreen.

Subwoofer Frequency Test is a free audio test app that lets you measure the lowest frequency that your speakers can play. The app uses a precise audio analyzer to measure the frequency and the sound level.

This app is a great tool to use to check the quality of your speakers and the frequency range of your audio system. It is also a great tool to use to test the sound quality of your car speakers and the bass level of your music.

This app is very easy to use. Just press the Start button, and the app will start measuring the sound frequency. Press the stop button to stop the measurement. The results will be saved in a log file, and you can use it to compare the results with other measurements.