When you first launch Prelude Live Logger on an iPad running iOS 7 you will be presented with this dialog requesting the app have access to your microphone.
Live Logger can be synchronized to timecode coming from devices from our partners at Timecode Buddy and Ambient Recording. The Clockit devices from Ambient Recording send their timecode to Prelude Live Logger through a cable that sends the timecode as an audio signal. Therefore Live Logger needs access to the iPad's audio input.
If you choose Don't Allow and later want to grant access, you can enable it in the Microphone section of the iOS Settings app. There you can enable Microphone access for Live Logger.