MindoculusBut for live musicians that is not an option. We can't risk the inaccuracy of a phone microphone nor the inconvenience of having to get the strings of the instrument close to the phone. We have to be quick and inconspicuous when we tune, getting out your phone, booting up an app and having to deal with that is not in my definition of inconspicuous nor quick. Having either a pedal or clip on tuner is much quicker. Click a button, tune and done.