Hopefully this will prevent people from constantly making the audio log topics.
Solo: You can get logs at any time. If you have beat the game, just load up Mombassa Streets and find the rest of your logs until you have 29/30. At this point, save & quit. Back in the lobby, load up Data Hive and get your final log. You will notice that when you try to load Data Hive, it will tell you that it is deleting your progress except for your VISR Comm Logs (audio logs), so don't worry about your logs.
Co-op: You have to get all of the logs BEFORE you start the Data Hive chapter. You can get them as you go along, or just get them all before you play the Kikowani Station flashback. When playing in co-op, if you go back to the lobby and try to load up a different chapter, it will DELETE YOUR AUDIO LOGS.
A map for the audio logs can be found in the achievement guide or here