Fundamentals
Audio recovery: WAV, recorders and takes
With audio, a tiny header often decides whether an hours-long recording opens at all.
The short answer
The audio data can be complete even when the file will not open.
A WAV file consists of a small header area and a large block of raw PCM data. If a recording is interrupted before the recorder finalises the header, the audio data remains — no program simply knows how to read it any more. That is the most common audio case.
01 / Structure
Why audio differs from photo and video
WAV and BWF usually store sound uncompressed as PCM. The actual content is therefore one continuous block of data without complex internal structure. That is an advantage: even when management information is missing, the raw data is often present in one piece.
The drawback lies in the header. It holds sample rate, bit depth, channel count and the length of the data block. If those values are missing or zero, no program will open the file — although minutes of material sit behind it.
For very long recordings RF64 comes into play, an extension for files above four gigabytes. Some recorders switch to it automatically, which has to be taken into account during recovery.
02 / Recorders
What to watch with multitrack recorders
| Situation | What happens | What to watch |
|---|---|---|
| One take, several tracks | The recorder creates several files | Check all tracks of the same take together |
| Recording interrupted | File header not finalised | File will not open, data usually present |
| Card full in the recorder | Last take incomplete | Check length against expected duration |
| Polyphonic WAV file | All tracks in one file | Check the channel count after export |
| Timecode recording | Timecode in the header area | Re-check sync after recovery |
03 / Procedure
The safe route
- 1
Switch the recorder off and take out the card. Do not start a new test recording on the same card.
- 2
Note the sample rate, bit depth, track count and approximate length of the lost take.
- 3
Create an uncompressed image of the card and work only with that.
- 4
Scan deliberately for the audio formats used, such as WAV, BWF or RF64.
- 5
Export to a different drive and keep the take file names.
- 6
Open each track individually, check duration and channel count, and check the tracks against each other for sync.
A short test recording on the same card, just to see whether the recorder still works, can overwrite exactly the sectors holding the lost take. Test with a different card.
04 / Verify
How to recognise a complete recording
- The displayed duration matches the expected length of the take.
- The channel count matches the recorder setting.
- All tracks of a take are present and run in sync.
- The file size fits arithmetically with duration, sample rate, bit depth and channel count.
- There is no digital noise or abrupt silence at the end of the recording.
- The file does not carry the .UNVERIFIED marking.
Common questions
The recorder died mid-take. Is everything gone?
Usually not. The PCM data is normally complete on the card; only the file header was not finalised. What matters is not writing to the card afterwards.
How do I work out whether the file size is plausible?
For uncompressed PCM: sample rate times bit depth times channel count times duration in seconds, divided by eight, gives the approximate size in bytes. At 48 kHz, 24 bit and two channels that is roughly 17 megabytes per minute.
I only find one of four tracks. What now?
Check whether the recorder writes polyphonic files where all tracks sit in one file. Otherwise keep scanning deliberately and compare timestamps: tracks of the same take usually carry the same start time.
Can File Recovery Hero repair a damaged WAV file?
Importing individual damaged files is not part of the scanning scope. The software examines devices and images. What is reconstructed from a supported source is, however, verified before success is reported.
May I make a test recording on the same card after an interrupted take?
No. A test recording can overwrite exactly the areas holding the interrupted take. Remove the card, create an image and check what remains on the copy only.
Can I recover a multitrack recording completely?
That depends on whether every track is still readable. Check all associated files together for duration, file size and synchronisation; one intact take does not prove that the other tracks are complete.
Your recorder in detail.
Zoom recorders, field recorders and podcast takes each have dedicated walkthroughs.