SUS4 Tuner

SUS4 Tuner is a chromatic tuner for iPhone, iPad, Mac and Apple Watch. Play a note and it shows the nearest pitch, how many cents sharp or flat you are, and changes colour the moment you are within five cents. Presets cover guitar, bass, ukulele, the violin family, banjo, mandolin, brass, woodwind and more, with alternate tunings alongside standard.

Alongside the needle there is a strobe view: the bars drift one way when you are flat and the other way when you are sharp, slowing as you close in and settling when you hit the note. Stage view enlarges the readout so you can read it from a music stand, and the A4 reference can be set anywhere from 430 to 450 Hz in 0.1 Hz steps, with quick picks for 415, 432, 440 and 442.

The Apple Watch app is a tuner in its own right: it listens through the Watch microphone, shows the note and cents on a needle, and taps your wrist when you land in tune, useful when your phone is across the room or mounted on a stand. It has chromatic, guitar, bass, ukulele and violin modes and its own A reference setting.