I have an iPhone 10 XR and a sena 20 s evo both up to date on the latest firmware. Whenever I start a route on my headset the volume of the turn commands is extremely low and I cant hear them. The only way that I've found to get around this is to start playing music (on my phone) because for some reason the commands are much louder then and it lowers the music volume when it plays a command. 

I have tried turning up the volume dial while a command is playing but it is already at maximum volume. I also have my iPhones navigation command setting turned up to "Very Loud" which is the loudest option. 

If anyone could steer me in the right direction I would be very grateful.