I'm from Brazil, and my bv7000 is with the super low call audios. Is there any way to increase this audio because it does not have its root installed?

Is your sound to low or that from the other people on phone?

Someone had solved their problems through this way:
"To enter the engineers code go to phone and dial pad and enter the code.
*#9646633#
You are now in engineer mode with the top tab telephony.
swipe across until you get to hardware testing.
select audio
select volume
select voice
you will see the drop down menu for receiver, hac, headset, speaker.
select either receiver or speaker
manually change UL gain to say 240.
scroll down the screen and hit the button Set.
go back using < key.