How to turn on the earpiece and main speaker at the same time?

Question

Mobile devices

Good day. Xiaomi phone. I want to make stereo sound of music simultaneously from 2 speakers (conversational and main), using the "Stealth Player" application, I managed to start music only on the conversational speaker. The iPhone has this feature. Tell me, please, what applications are there or, maybe, through the engineering menu, you can enable such a function. Thank you for your time!)

Answer 1

The iPhone does not have these features. And the speakers there are completely different ... Ditch it ...