I noticed some strange things about the volume of the GPS voice guidance. For one, I haven't found any way to adjust the volume. Another odd thing is that if you have music playing, the GPS voice can easily be drown out by the music. It doesn't mute the music for GPS directions. And on top of all of that, even if you attempt to turn down the volume of the music while the GPS is talking, the volume control stops working while it's talking. The only hope in that case is to press the button to shut off the music.