One of the great new additions to Windows Phone 8.1 is the ability to assign custom notification sounds for your apps. Previously, in Windows Phone 8.0 Update 3, developers could ship their own sound to be used, but only a few have taken advantage of that so far. But in 8.1, via the Notification Center, you can configure apps independently, including for alert sounds.
Melodia is a simple app, and it’s free. It’s basically a repository for ‘official’ alert melodies, which you can then play to sample and save directly to your phone. Once saved, they will appear in your custom alerts and by using the Notification Center, you can assign them to apps. Sure, you can do this on your own, but this is much easier using this app.