An experiment for you.
Plugged the Lenovo headphone out into the TAPE INPUT of my little Behringer mixer.Set the MASTER to 0. The TAPE IN has no other controls. Took one of my tunes and played it. 70% output on the Lenovo drives the mixer LEDs to 0. So.............
Something is wrong with his Lenovo, the PA OR the songs are mixed way to low.