Low Voice Volume
When playing music while navigating, the volume of the voice instructions can be low compared to the music. Increasing the overall music volume does not help in these cases as it makes the music volume too loud.
Since Scenic version 2.2.4 (released 25 feb 2020), Scenic has the ability to boost the voice volume above 100%, to max 130%. Scenic Settings > Sound & Haptics > Voice Volume.
Increasing the volume above 100% increases the voice volume itself, but also makes the voice more crisp and clear which make it better to understand over helmet wind noise at higher speeds.