Invert (opposite phase) the sound taken from microphone and output it to speaker.
It's a simple noise canceling app.
Since it is made with the minimum program, if you have a smartphone with high processing speed, you might be able to keep quiet inside of your car or your room.


※For smartphones with battery saving mode,
　Auto-startup and background services may not work correctly.
　In that case, Please allow it yourself from the individual app settings on the system settings menu.