When playing music, and using inbuilt nav, the music cuts off from left speaker and nav guidance starts speaking. This is great for those who need it. I dont like voice nav prompts and want to disable it. I could turn down the nav guidance volume, but that mutes my android assistant speak-back when I use it. On google maps, I have the option to turn off voice prompts but I cant find any option on the inbuilt nav to do so. Any tips?