Accordion tuner with scope, spectrum and strobe. Can show up to eight different notes or reeds concurrently.
Hold the phone/tablet near the instrument, play a note and observe the display. In portrait the app shows a scope with the input signal, a spectrum showing the processed signal, the main display with the note value, cents error, frequency error etc, a strobe display and a meter display showing the cents error. In landscape the app shows just the main display and the meter. There is a signal indicator in the action bar which is useful in landscape mode.