This is a professional Guqin tuner. It is designed to tune a 7-String ancient Chinese zither, i.e. Guqin.
We have been focused on musical instrument turning for more than 10 years. We designed and manufactured a large number of popular professional digital tuners, as the upgrading, we recommend this App.
Its easy to use, pluck a string of Guqin, as the sound goes into the mobile phone, 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.