A free program for Android, by TarrySoft.

The free Trombone tuner app is a handy tool that can tune a musician’s Trombone with great accuracy and little effort. It is used by musicians to tune their instruments. It is designed to work with any kind of Trombone, and works perfectly on both Android and iOS devices. The app can also work as a standalone tuner, meaning that it can tune a musician’s instrument even when the instrument is not playing a note. The sound is analyzed using the built-in microphone, and the frequency of the note is displayed on the screen. The user can then choose to tune the instrument, by choosing one of the presets or by manually setting the note played and the frequency.