DavidPJ said:
Good idea. I didn't realize that button muted the audio system.
I confirmed today that the mute button on the steering doesn't mute the NAV annoucements, just the music. So this solution works great. The other solution posted by mdh4psu for tuning to an unused channel also works great.
I also learned there are actually 2 different volumes, one for the NAV annoucements, the other for music. While an announcement is being made, quickly turn the volume control and the screen will show NAV volume and adjust it accordingly. So if you turn the volume control in normal music mode all the way down, you will still be able to hear the NAV annoucements.
What could be confusing is if you accidentally turn the NAV announcement volume all the way down and don't know it. The only way you would know it is down is if your music level keeps dropping in and out while you have a programmed destination but there are no NAV audio annoucements.
Regarding the configuration choices for turning on/off the voice prompts, that's not the problem. I didn't want to turn off the voice prompts with the NAV screen displayed, I just wanted the music audio off.