Mausoleum Suite

Mausoleum Suite is a suite of songs included in the Halo 2: Original Soundtrack. It includes Destroyer's Invocation, Falling Up, Infected, and Shudder. Falling Up, which plays when the Arbiter gets his armor, is often referred to as the "Arbiter's Theme,"as it is always played in Halo 2 during Arbiter missions. It is also heard on the level Floodgate in Halo 3, heard when the Elites join up with the Marines inside the Flood infested Voi, indicating that the theme has come to represent the Covenant Separatist movement as a whole. The beginning of the song, and the end of Shudder, use sound effects from the stand-alone song Ancient Machine. Infected starts with a slow tribal beat, and vocals similar to Ancient Machine, before descending into cascades of chaotic synth effects and distorted guttural vocals(which may be another secret message). Shudder is a remix of Shadows from the Halo: Original Soundtrack. This melody is usually played in association with the Flood, as their de facto theme.

Hidden Message
When the track is played backwards, a hidden message can be heard. At normal speed it is inaudible, but sounds similar to the Gravemind's voice. However, when sped up words can be heard and the voice begins to sound like that of a Prophet. It is more likely that it is 032 Mendicant Bias because Gravemind or the prophets wouldn't be seeking for forgiveness nor does Gravemind do anything that may warrant a reference to "living in a prison of [his] my own demise", but this may be a reference to his being trapped on Delta Halo. Whether either is the owner of the mysterious voice, or something/someone else is debatable.

Trivia

 * The beats of the song have a striking resemblance to the beats heard in the theme music for Marathon 2: Durandal.