I play with a headset, (Logitech G35), and yesterday I noticed in-game that the right side is much louder than the left.
I've checked my headset on other devices, reinstalled drivers and checked other games, so far, it's just Destiny.
edit: it seems to be certain audio that is problematic:
the music is in both channels, just louder to the right
jump fx is right only
However, other things are as they should. Example the fx played when choosing a character is front and centre with no issue.