This trophy is for listening to 5 songs in the gallery. The gallery menu option is blue and shows a picture of two girls to the left. Once you've entered the gallery, press
and you'll see a few options. Choose one, then select a song. Simply back out and press right or left to choose another song. Repeat this 5 times with different songs. You don't have to listen to them all the way through in order for them to count.