Prerecord keeps incoming audio in an internal buffer, so if you press the record button up to 10 seconds too late, you’ll still have your audio. You can choose to buffer up to 10 seconds of audio in Nova, Nomad, and Deva.
From the point the recorder is powered up, any sound coming in from any input is always being processed whether or not you’re recording. So when pre-record is enabled, the processed signal is held in a buffer that’s constantly being refreshed. When you press the RECORD key, the audio stored in the buffer is included the current take with the corrected timecode. Since the recorder is always processing the incoming audio, no additional battery power is used when prerecord is engaged.
Please note, the pre-record buffer is dumped after any of the following settings are changed: sample-rate, timecode, user-bits, frame rate, and track count.