Summary
Marty in the Halo 3 Announcement Trailer documentary.
Marty O'Donnell (aka Marty, the Elder) is the Audio Director at Bungie. He has written the music for Myth, Oni, and both Halo games. In both Halo 1 and Halo 2, he is the voice for Jackals, Hunters and Flood.
Marty's sound studio is called the "Ivory Towers", which is very similar to the name of a multiplayer map in Halo 2, Ivory Tower. In addition, this tower is noted to be owned by a character named Lance O'Donnell.
Before working for Bungie, he did audio work for several TV/radio commercials including Flinstone Vitamins. He was once co-owner of TotalAudio, a company that produced sound design on Riven.
He is currently the arch enemy of Frank O'Connor.