12 January 2026 | 6 min read
What is a poly WAV, and why does your editor keep asking for mono files?
Boom, lavs, plants and a mix, all inside one file. Poly WAVs are the default on modern field recorders, and the first thing many post workflows reject.
If you have ever handed a day of production sound to an assistant editor and received a polite message asking for mono files, you have met the poly WAV. It is not a broken file and it is not an exotic format. It is simply the way most field recorders write multitrack audio.
The definition, without the jargon
A polyphonic WAV (often written polyWAV or poly wave) is a single WAV file that contains several audio channels interleaved sample by sample. One file, eight tracks. The alternative is a monophonic set, where the recorder writes one file per track: TAKE01_1.wav, TAKE01_2.wav and so on.
Both come from the same recording. The difference is packaging. Sound Devices, Zoom, Zaxcom, Tascam and Aaton recorders all default to poly because it keeps a take together as one object, with one set of metadata, one timecode stamp and one file to copy at wrap.
Why poly is good on set
- One file per take means no risk of losing track 6 during a card transfer.
- Metadata such as scene, take, notes and track names is written once and stays attached.
- Timecode and sample rate are guaranteed identical across all channels.
- Card management is faster, and checksums are simpler to verify.
Why poly is annoying in post
Many editing systems, sound libraries and delivery specs expect mono stems. An 8 channel poly file imported into a timeline can arrive as a single clip whose channels are locked together, or worse, get summed to stereo by an import setting nobody noticed.
Dialogue editors want to open boom on one track, lav on another and a plant mic on a third, with names that mean something. That means splitting the poly file, ideally without touching sample rate, bit depth or the original channel order.
How to split a poly WAV correctly
A correct split does three things: it deinterleaves the channels bit for bit, it keeps the original sample rate and bit depth, and it names each output using the track names stored in the file rather than generic numbers.
That last point matters more than people expect. A recorder stores track names in the iXML chunk or in the bext description field. If your splitter ignores them, you get TAKE01_1 through TAKE01_8 and somebody has to listen to all eight to find the boom.
The poly WAV splitter on this site reads those names, shows you the channel layout, lets you rename anything before export, and packages the result as a ZIP. It runs entirely in your browser, so confidential rushes never leave your machine.
When you should keep poly files
Archiving. If you are storing a shoot for the long term, keep the original poly masters untouched and split working copies. The poly file is your source of truth, complete with metadata, and it will survive format churn better than a folder of loose monos.