Audio · exFAT field recorder card
Poly WAV multitrack: recover after an interrupted recording
What can I do with multichannel Poly WAV takes after a recording interruption?
Short answer
Often recoverable on a copy: an interrupted Poly WAV usually has its audio but no final chunk sizes. Correct the sizes on a copy and keep the channel count exactly as recorded; one wrong channel or block size shifts every track, so microphones swap or turn to noise. Use your track sheet to check each channel.
The situation
multichannel Poly WAV takes is missing, too short or unreadable after power loss, a card error or an unsafe stop.
An interrupted take usually exists on the card with its audio already written, but without the final chunk sizes the recorder normally stamps when you press stop. Players read the header, find a length of zero and refuse the file, even though the samples are there.
01 / Diagnose
Work out what actually disappeared
Power loss, a flat battery, a card error or pulling the card mid-take stops the recorder before it can close the file. A canonical WAV header is 44 bytes and its size fields are filled in at the end, so the directory entry may show zero bytes or a fraction of the real length. The channel data itself is written continuously as the take runs.
The payload may have been written before duration fields, indexes, directory entries or closing structures were committed. For Poly WAV multitrack, this matters because several microphone channels share a container, timecode and common length
Check the last known path, trash and backups without writing to the original device.
02 / Protect the source
Preserve the best recovery chance
- 1
Switch the recorder off, remove the card and leave it out; never let the device offer to finalise or fix the take on the original.
- 2
Note the exact channel count, channel order, sample rate and bit depth of the session; every later repair depends on those four values being right.
- 3
Copy the truncated file, or an uncompressed image of the whole card, to a working drive and do every repair attempt on that copy.
- 4
Rewrite the size fields on the copy with a WAV repair tool, then import the result and listen to each channel separately.
Do not restart the recorder with the same card to continue the session, and do not let any tool write a corrected header back onto the original file. One wrong channel count or block alignment shifts every sample, and the take turns into noise.
03 / Choose the method
Match the tool to the source
For stable, readable exFAT, NTFS and FAT16/FAT32 or uncompressed IMG, DD, RAW and BIN images.
Unconfirmed exports are marked .UNVERIFIED.
File Recovery Hero recovers files from exFAT, NTFS and FAT16/FAT32 cards and from uncompressed images; it does not repair a damaged individual file. Fixing broken WAV size fields is the job of a repair tool working on a copy, and audio never written to the card is gone.
04 / Verify
Check the recovered content, not just its name
A repaired take reports the same channel count as the session, and each channel carries the source it was patched to: the lavalier on its channel, the room pair on theirs. Playback runs to the point where the recorder stopped, then ends cleanly instead of ending in static.
Keep the source until two verified copies exist. One working preview is not enough.
Sources and technical references
FAQ
Questions about this recovery case
Can exFAT field recorder card be recovered in this situation?+
An interrupted take usually exists on the card with its audio already written, but without the final chunk sizes the recorder normally stamps when you press stop. Players read the header, find a length of zero and refuse the file, even though the samples are there. The result still depends on what remains readable on the source.
What should I avoid before scanning?+
Do not restart the recorder with the same card to continue the session, and do not let any tool write a corrected header back onto the original file.
Does scanning write to my memory card?+
Your memory card is only read. Nothing is saved to it.
How do I know whether the result is complete?+
A repaired take reports the same channel count as the session, and each channel carries the source it was patched to: the lavalier on its channel, the room pair on theirs.