My own getCurrentlyPlayingNote?

Hi, I need to set whether my voice is playing or not?
I see there’s a getCurrentlyPlayingNote function but I can’t seem to override it or change the variable.
How do I set this please? Do I really have to write my own voice implementation?

edit OK I can override the other function ‘isVoiceActive’ though, I just forgot the ‘const’ at the end when I tried it. DOH!