If you work in film, television, or live sound, you've probably encountered polyphonic WAV files, often called poly WAV. They come from field recorders, DAW exports, and broadcast equipment. And if you've never had to work with them before, they can be confusing.
This article explains what poly WAV files are, when you'll encounter them, and how to manage them efficiently.
What is a polyphonic WAV file?
A standard stereo WAV file contains two audio channels: left and right. A polyphonic WAV file contains more than two, anywhere from 3 to 32 or more, all stored in a single file. Each channel is a completely separate audio signal.
Field recorders like the Sound Devices MixPre and Zoom F8 record poly WAV by default. If you had 6 microphones running simultaneously, the recorder writes all 6 channels into one file. That's a poly WAV.
When do you encounter poly WAV files?
- Location sound recording: field recorders create poly WAV when multiple microphones are recorded simultaneously
- DAW exports: some sessions are exported as multi-channel WAV stems
- Broadcast audio: 8-channel delivery files used in television broadcasting
- Archival recordings: multi-track recordings from live events or studio sessions
Splitting a poly WAV into mono files
Post-production editors often need individual mono files rather than a multi-channel poly WAV. Most NLEs can import poly WAV, but working with individual mono files is cleaner and more compatible with different workflows.
Wave Copilot splits a poly WAV in the Split Poly tab, and it does more than pull every channel out on its own. A routing matrix decides what comes out: each row is one output file, each column is one input channel. Leave it at its default and you get one mono file per channel. Tick several channels into the same row and that row becomes a single multi-channel file, which is how you export a poly with the channels you don't want left out. Clear a row entirely and it is skipped.
Files are named '{name}_{channel}.wav' by default. If you'd rather have the track names in the filenames, so a channel your recorder called 'BOOM' comes out saying so, switch the Output Filename section to Custom and drop in the Track Name chip. Either way, the metadata goes with the audio: iXML, bEXT, and the track names themselves are written into every split file.
Combining mono files back into poly WAV
The reverse operation is equally common. If you have a set of processed mono files that need to be combined into a single poly WAV for delivery, or to send back to the mixer, Wave Copilot handles that too, and it handles the messier versions of the same job.
- Combine Mono merges separate mono files into one poly. Batch mode picks up the multi-mono groups it already found in your file list; manual mode lets you choose the files yourself. A routing matrix sets which file lands on which output track, and any track you leave empty is dropped from the output, so you can rebuild ISO tracks only.
- Combine Poly merges two poly files, typically a main multi-channel recording and the separate stereo mix that 32-bit float recorders have to write as its own file. Pairs are matched automatically by timecode.
- Combine Group merges any number of files of any channel count, grouped automatically by timecode, sample rate, and length. This is the one for a mixed rig, an LCR setup recorded as a mono file plus a stereo file, for instance. Here you can drag the output channels into whatever order you want, interleaving channels from different files, and rename each one before writing.
All three cap out at 64 channels, which is also the ceiling for playback, and anything over 4 GB is written as RF64 automatically.
Conclusion
Poly WAV files are the standard for professional multi-channel audio recording and delivery. Understanding how to split, combine, and manage them is a core skill for anyone working in audio post-production or location sound. Wave Copilot's free trial is the fastest way to try it in your own workflow, on Windows, macOS or Linux.