We have provided here the Halo 3 Odst Log locations and Halo 3 Odst achievements which are leaked by the Game-tuts via Youtube. The videos of Halo 3 Odst Log locations and Halo 3 Odst achievements are shown below.
Halo 3 Odst Audio Log Locations
On the level Data Hive, after collecting all 29 Logs, then only 30th audio log can be found. Alone or with another ODST, find all Audio Logs or find 3 Audio Logs. To unlock, complete NMPD HQ on Normal, Heroic, or Legendary. You will get the Audiophile Achievement for 75G, after collecting all 30 audio logs.
See the Halo 3: ODST Hints & Cheats, Yet another Take, (X360) Developer Interview and all videos of Halo 3 Odst Audio Log Locations here(http://chanelnews.org/halo-3-odst-audio-logs-locations.html).
Check here for the video of this – http://www.youtube.com/watch?v=lMA_9Y9f9Vc