On the level The Covenant, go to the part where you meet the Arbiter and the Monitor at the bridge.
Get a hornet and fly to either the left or the right side of the building, get off the hornet and walk up the ramp, get as high as you can and wait.
It will become a little quiet and Microsoft Sam will start singing a song.
Now its not really either one but i just can't remember which one, though it still works.
Enjoy!
