I found a way how you can have higher audio volume.
First go to the OS ENGINEERING SCREENS then enter AVP CALIBRATION then enter WIFI MB COMP LIM then scroll down after reach GAIN5 and change this to 4900
Now your volume is much much loader, I use a bold 9000 and can listen with more pleasure
What for the others gains, I go to find out.
Notice that after a batt pull the settings are as default and you have to change it again.
Enjoy DelftEo