Improvement....
On the old headunit, there was an option to select the navigation software, just like on the DUDU. For sound, there was a solo volume selection for navigation, a pull-down "potentiometer" 0-100%. It worked so that a person also set the volume level of the navigation and it spoke at the set volume regardless of how the main sound volume was set. So even if the radio or some player played weakly, the navigation spoke loudly enough... At the same time, the volume control was switched - if the navigation did not speak, the volume control controlled the volume of the radio and players, when the navigation started speaking, the buttons went to control the volume of the navigation. Maybe it would be useful to someone else. THX
