The Zumo 595 which has a Spotify App and connects to Spotify via the Garmin Smartphone Link App. This gives the Zumo 595 the ability to Browse through the music categories and to select Albums, artists , playlists etc from Spotify and control it through a media player type app. You have to load the Spotify App on the phone first. It sounds brilliant in theory, but I find it very clicky in the earphones - to the extent that I decided I didn't want that, and resorted to using my mp3 files on the Zumo if I wanted music.
The Zumo XT does not have a separate App for Spotify. The Music App on the XT will pick up the smartphone as a music source and the controls to play, pause, skip forward and back will all control whatever the Smartphone is playing. So if the smartphone is set up to play a playlist on Spotify, the XT can control that playlist. If you want to change to a different album, playlist or artist, then you have to do that on the smartphone itself.
The same applies to radio programs and any other music being played on the smartphone. I have not yet found a way that it is able to get hold of raw mpr3 files on the smartphone - without them being played by a media player on the phone - although that may be possible.
It seems that basically, the browse feature is disabled when getting sound from the smartphone - you can just skip fwd and back, play and pause. Brose is available when the MP£ folder on the Zumo XT is selected.
Today, I discovered something really important. I found another way that doesn't work.
Thank you jfjeath for the info - I've been wondering why I couldn't browse music like I used to on the 595.
This is a massive backward step for Garmin, along with the ludicrous choice to go with an outdated usb format.
Shame, because the XT is otherwise a much better device.
