I'm using the oneplus one running cyanogenmod 11S. This includes an app called AudioFX which uses a google API to apply EQ etc. to all audio sources implementing the API. Poweramp appears to not implement the API because the AudioFX settings do not affect the output from Poweramp. The EQ etc. baked into Poweramp are excellent, however there are features in AudioFX which are not in Poweramp. These include automatically applying different audio parameters according to the output, e.g. headphone, bluetooth, speaker, etc. Either implementing the google API, or adding output-based audio settings would be EXTREMELY great. EDIT: This actually DOES work! Turn on MusicFX in the Tone/Vol menu and long press will take you straight to AudioFX.