The DSP Audio Filter is a tool that enables you to filter frequencies from an audio spectrum by using your cell phone's microphone. This app was originally programmed for Ham Radio (Amateur Radio) operators to remove unwanted background noise and improve SSB and CW signals (Morse Code) but it can be used in different other ways.
This download is completely safe. Wolphi LLC has designed this application that falls into the Communication category. The developer released a new version of DSP Audio Filter on Feb 26, 2017 and over 1K users downloaded and set up the app.