App: iChromatic Strobe Tuner
Developer: HotPaw Productions
Genres: Music, Education

Professionals use strobe tuners for the most precise and responsive tuning of musical instruments.  See the pitch of difficult to tune instruments bend slightly sharp or flat in real-time as you tune.  The display of responsive high-contrast rotating strobe visualizations enables rapid and extremely accurate tuning.  More familiar-looking tuning dials and fine tuning meters are also available and visible below the two strobes. Also see notes appear on a keyboard image and a musical grand staff as a great musicianship learning aid.

Make a strobe stop spinning, and your note will be in tune with the indicated note. Spinning slightly clockwise, and this indicates that your note is slightly sharp. If the strobe is spinning too fast to see, then the note is way out of tune. 

The strobe on the left does automatic note detection.  The strobe on the right is set manually to one note, which is useful if there is too much background noise for automatic note detection to function properly.  The popup button above the strobe on the right can be used to select the note, or you can use the up/down cursor keys to adjust the note for tuning.

For high background noise situations, a multi-strobe mode that displays strobes for all 12 chromatic notes, simultaneously, can be helpful.

For those who prefer tuning dials and fine tuning meters, those are visible below the two strobes.

The Concert A frequency can be customized in Preferences.

The approximate working range is from 2 octaves below to 2 octaves above Middle C, depending on the microphone being used and the volume settings.

For your iPhone and iPad, please see the HotPaw inTuna Strobe Guitar Tuners and iChromatic tuners in the iPhone/iOS App store.

Release notes:
New: Enhanced support for the latest Macs and macOS operating system releases