Pitch graph is a versatile tool for musicians to tune instruments and practice intonation. Use it when practicing the violin, viola, cello, trumpet, singing and much more. The app monitors the microphone and calculates the frequency up to 40 times a second and plots it on a 3D accelerated graph. It has a maximum detection sensitivity of a thousandth of a cent. The app provides real time feedback while you play your instrument. The blue lines in the background represent the note frequencies. The closer the plotted line is to a blue line the better the intonation. Intonation is also indicated with three colors: Red for notes that are too sharp, orange for notes that are too flat and green for notes that have good intonation. The app automatically monitors the microphone and removes intermittent noise and silence, while keeping the sound and pitch information on the graph synchronised. Tap a location on the graph and it plays the corresponding sound which makes it easier to read the graph. A practice session can be reviewed with the replay feature. This animates the graph while playing back the sound and is a great way to find problem areas in a performance. The clear button resets the app when you are ready for the next take. You can turn the microphone on and off by tapping the microphone icon. To make the most of the app please be aware of the following limitations: The graph refresh rate is throttled on older hardware to improve pitch detection performance. The app can resolve only one frequency at a time, so bowing double stops on a violin or strumming a guitar will give incorrect pitch readouts. Because the app uses the microphone it may pick up other sounds such as background music. Pitch detection works best in a quiet setting. The app was tested with a number of different instruments, yet each instrument is unique, so performance may vary. I hope you enjoy this app and find it useful.