> I never dare to try if not alone

Yes, this was me. My confidence has improved through practise to a point where it only half killed me to post that demo video. My family still ask me to relocate when I'm doing this around them... so I think you can hit the pitches and still not sound amazing.

Unfortunately, the way it works, and to avoid any copyright issues, it can't really operate on phones because you can't listen to other apps on them. Maybe the only way is to share your learnt pitch tracks (trained on the laptop) with a mobile companion app.