Upon cashing in 3000+ or more Kudos via a checkpoint or offensive skill, a special pendant will become available to be synthed. When equipped, it will cause a specific Anthem to be played instead of the usual randomized track. Where each song can be earned.

Audiolocket	How to unlock
Audiolocket 1: Beyond the Blue	1st Sumeragi
Audiolocket 2: Nebulous Clock	Subaquatic Base
Audiolocket 3: Azure Door	Media Tower
Audiolocket 4: Pain from the Past	Biochem Plant
Audiolocket 5: Scorching Journey	Datastore
Audiolocket 6: A Zip to the Moon	Pharma Lab
Audiolocket 7: Rouge Shimmer	Stratacombs