This app is only for professional pipe organ builders and technicians. It addresses the special tuning needs of building and maintaining pipe organs.Notable features:* Covers the note range of C0 (32 pipe) to C9 (1/16 pipe)* Handles mutation ranks (Quint, etc.) and Celeste ranks* Built-in compensation to track temperature changes* Calculates pipe cutoff for trimming new pipes to length* Precision strobe-like display for very precise tuning* Can be calibrated to an accuracy of 0.02 cents* Provides many historical temperaments for period music* Switches notes automatically up to 4 notes away* Provides a versatile display of the frequency spectrum* Wireless control of MIDI-enabled organs for key holding and stop selection using a Bluetooth MIDI adapter.Organ Tuner has two different displays that are visible at once. One is the strobe-like Phase Display. This is a band where black squares move left or right. You tune to make the squares stop moving. The other is a frequency Spectrum Display. This is a graph that shows a peak for every pitch present in the sound. You tune to make a peak in the graph move to a central red line. Having both the Phase Display and the Spectrum Display visible at once gives you a more complete picture of the tuning than any single spinner-type or needle-type display.There is an extensive built-in context-sensitive help system in the app. A detailed users manual is also available at our support web page. You should download and read this manual before buying this app.