So I haven't found anything while searching so let me know if anyone else has ever had this happen. I have a 2015 crosstrek limited with all the bells and whistles and one that I can't understand. While driving in any condition occasionally it will fade out the radio volume, if the radio is on, and make a single "ding" tone the. Fade the music back in. It is not part of the eyesight system as it is a different pitch and in too many different conditions for it to be that system. I do not have a destination planned in the nav system, but it does sound like a nav tone. The dealer has not been much help with this thus far, but it will be getting its first oil change in a week and I am planning to give them some time to try and figure it out more then. Just curious to see if anyone else has ever had this problem. Thanks for any info.