We have been focused on musical instrument turning for more than 10 years. For these years, we have designed and manufactured a large number of popular digital tuners. As the upgrading and replacement, we recommend this App. This App is easy to use, pluck a string of Banjo, as the sound goes into the mobile phone, our App will accurately identify the string and the deviation of frequency in cents. App only responds to musical tones in certain frequency range, while filtering out other interference sounds.