sorry that i pay no attention to that post.
and sorry again that the voice gain in the factory settings page doesn't help to the navigation sound volume in fact and i mislead you before.
For the navi sound , you need to enter settings - car settings - navigation page and adjust the navi sound rate (see picture).
Ok, I will try that.. Can you still answer the following questions...
Hi Jammy, I need more information on the gain controls.
Does the radio gain only control the radio sound?
Which gain controls the Music Player?
Which gain controls the Video Player?
In addition to beeps and key tones what else does the system gain adjust?
Also can you find out what the Amplifier gain controls?