Why can't doubler pick up pre-recorded sounds

Sometimes I don’t want to sing through the mic all the time I’ll pre-record the sound on my phone for a melody but doubler seem to can’t pick up the melody.
Through my phone speakers, and I have a note 10, these speakers are super loud so this shouldn’t be a problem help me

Hi Ralph

Dubler is just aimed at real time voice to midi translation, and this is what our pitch algorithms are trained for. They won’t be able to accurately translate a voice recording from a phone speaker due it to not having the qualities of a real human voice that the software is listening for

There’s other programs out there that do pitch to midi based on pre recorded audio, but it’s not our focus with Dubler. If you have any questions about this let me know!