Arabic & Turkish Oud 15 kinds of tuning modes are available. With noise filtering can help you tuning strings with simple setting while activating the APP. First step is choose the frequency at top of screen, then choose the tuning at the middle of the screen. When you pull the string, the pitch will be shown on the panel for the individual string by indicating signal high or low. [Function Description] - Calibrate Sound : Click on an open string then calibrate the sound with your instrument.