my device accidently loose ability for playing all sounds (rings,audio e.t.c). The situation is same with headphone. The very silent and noised sound then I hear in speaker.
I suspect that problem is caused by locking the device in some stand by mode, because most often it occures after pressing the button when screen is blanck. the problem may be resolved by rebooting the device or waiting screen blanck and pressing any button again. I wouldn't upgrade to new ROM because I am native russian and as I understood the new ROM is only western eu. locale.