diapaSon is the perfect solution for tuning your musical instrument by ear! It emits pure musical tones ranging from 55 to 3000 Hz. Thanks to its highest standard of accuracy, diapaSon lets you change the frequency up to a precision of 0.01 Hz, and by halftone and octave steps. Last but not least there are NO ads, NO banners, NO in-app purchases: this app is completely FREE!