Audio Narrowband Filter app analytics for September 6

This app implements a audio filter around any selected pitch. The sound from the microphone is filtered and sent to a headset. The app features: * Adjustable bandwidth from 400 cents to 50 cents * Synthesized beat rates that can be switched on for beat rate recognition training. * Piano keyboard selection of the selected pitch * Spectrum analyzer display of the input sound * All functions explained through self-contained help document