Ok, forgive me because this is how my brain thinks to make things easier. This will be a step by step of what you can do to get your music (and it is the same info, just in step by step)
1) without putting the sd card in your x2, see if your music is there. If it is, then that means you have to connect your x2 to a PC to transfer your music off your x2 then transfer your music from the PC to your SD card (create a folder on your SD card labeled music and transfer your music into that folder).
2)if there is no music on your x2 without the SD card, then that means the music is on your SD card and all you have to do is get your Maxx to find it. On your Maxx, if your music player has in settings an option to scan or rescan, then do that. It should find your music.
or 2a) install poweramp, go to settings, select rescan, after that is done select Auto-find music folders. That should find any and all music on your SD card.
3) if step #2 does not work, then you will need to copy your files from your SD card to a PC or to a flash drive. After your files are safe on a PC or flash drive then format your sd card while it is in your Maxx. Once your sd card is formatted for your Maxx, you can transfer your music files onto your sd card on your Maxx into a folder labeled music (you may have to create this folder).
Sent from my DROID RAZR Maxx using Droid Forums