USB speaker stereo output problem (one side not working)

it was working good few days ago. now one speaker (left/right) is not sounding when i flashed a custom rom for test purpose (may be CM based). now um on AOSP based rom (5.1.1). but from the flash my usb speaker sounds only one side. after that i switched and flashed several custom rom but no solution. plz help me. i think its not for roms fault, because roms works correctly before .
is it kernel related problem? or something??
can flash of factory rom may bring solution?
device : moto g (xt1033)
(sorry for my bad English)