Bluetooth troubles with sony bt earphones

[buglife]

Hi! My Xperia L3 work in this way with my pair of sony earphones: I play music with an app and I listen till I put in standby my phone, becouse after 30 sec the BT connection fail, and reconnect few instant after, but by this app music go off and I have to unlock the phone and replay music, but after lock 30 sec after BT disconnect, and so it goes like this. This happened only in mobile band. If I listen music at home in wifi this trouble doesn't happened.

Someone knows if there's a tip or trick to work around?

Thanks

[buglife]

Always with my bt earphones sony, if you watch (and listen) youtube, there's no bugs, you heard everything without interruption, also in a  call conversation... But if you use a player like the defaut by sony, the problem persist, and bt disconnect and reconnect, after locked the phone.