How do I combine mono WAV files into one multichannel file?

Drop all the mono files on the merger above, drag them into the channel order you want, then export. Each source file becomes one channel of a single interleaved WAV; the first row is channel 1.

What is the difference between merging and mixing?

Merging is interleaving: every file keeps its own channel and its own level, nothing is summed. Mixing would fold several sources into a shared channel. This tool only interleaves, so a 5-file merge always produces a 5-channel file.

Do the files have to be mono?

Yes. A stereo or multichannel file is rejected with a message telling you how many channels it has. Split it into mono first, then bring the parts back here.

How many files can I merge at once?

Up to 12 mono sources in one poly file. Individual files above 500 MB need Pro.

Do the files need the same sample rate, bit depth and length?

Ideally yes, and the tool flags every file that differs from the first one before you export. If you export anyway, the first file sets the sample rate and bit depth for the whole export, other rates are resampled to match, and channels shorter than the longest are padded with silence at the end.

Will merging change my levels?

Not unless you ask it to. Each channel is written at its original level; the per-track trim next to each row is the only gain applied, and it defaults to 0 dB.

Can I set the channel order?

Yes, and it is the point of the list. Drag rows until the order matches the track sheet your editor expects, for example mix on 1 and 2 followed by boom and lavs.

Are the channel names kept?

The name shown on each row is written into the exported WAV as that channel's track name, so the file arrives self-describing. Names are edited inline before export; AIFF and MP3 output carry no track-name field.

Is this the same as building a PolyWAV?

Yes in substance. A poly WAV from a field recorder is an interleaved multichannel WAV, which is exactly what this produces. Keep the channel order consistent with the recorder's convention if the file has to sit alongside real poly takes.

Are my stems uploaded?

No. Decoding and interleaving happen in your browser and the merged file is written straight to your downloads.

Multichannel audio merger

Multichannel Audio Merger – Merge Mono Files into One Multichannel WAV

Turn a folder of mono stems, boom, lavs and plants, into a single interleaved multichannel WAV in the exact channel order you want. Every channel keeps its own audio and its own name, compatibility is checked for you, and nothing is uploaded.

1st conversion free
No installation
No plugin
Files stay local

Drop your mono audio files

WAV, AIFF, MP3, M4A, FLAC, OGG. Boom, lavs, plants: add them all, then set the channel order

Browse files

✓ 1st conversion free. ✓ Your audio stays on your device.

Watch how to merge mono tracks

What this tool does for you

Combine up to 12 mono WAVs into one interleaved multichannel file
Set the channel order your delivery spec asks for, by drag and drop
Name each channel and trim its level before the export
Mismatched sample rate, depth or length is flagged instead of silently fixed
Everything runs in your browser. Files are never uploaded to a server.

How it works

01. Drop your mono files
They appear as a channel list in load order.
02. Set order and names
Drag to place channel 1, 2, 3, then name each one.
03. Export the poly WAV
One interleaved file, source sample rate and bit depth.

Building a poly WAV from mono tracks

Why anyone merges back to poly

Poly files travel better. One take is one file with one timecode stamp, so nothing gets orphaned in a hand-off, and archives stay far tidier than a folder of thousands of loose mono takes. Many mixers also prefer a single multichannel file when conforming, because the channel relationship is guaranteed sample-accurate.

What must match before merging

All sources need the same sample rate, the same bit depth and the same length. A 48 kHz file and a 44.1 kHz file cannot share a container without resampling one of them first. Length differences usually mean the files came from separate takes rather than one synchronous recording, which is worth checking before you build a file that implies they are in sync.

Channel order is a delivery decision

Channel order carries meaning. A 5.1 stem set is ordered L, R, C, LFE, Ls, Rs in SMPTE order; a production sound set usually puts the mix on 1 and 2 with isos following. Getting it wrong is not an audio problem, it is a routing problem that surfaces on a dub stage.

Professional use cases

Post-production delivery

Assemble stems into the exact channel layout a distributor's spec sheet requires.

Location sound archiving

Recombine recovered mono tracks into one poly file per take for long-term storage.

Music production

Interleave separately bounced stems into a single multichannel file for a mixing hand-off.

Merge mono files into one multichannel WAV

Separate mono files are easy to make and easy to lose track of. A take arrives as Boom.wav, Lav_Anna.wav, Lav_Ben.wav and Plant_Car.wav, and by the time it reaches an editor somebody has renamed one, moved another and dropped a third. Interleaving them into a single multichannel file makes the take atomic: one file, one channel per mic, one order that cannot drift.

The merger does that and nothing else. It reads each mono file, lines them up in the order of the list, and writes one interleaved file where channel 1 is your top row. No summing, no normalisation, no fades.

Interleaving is not mixing

The two are confused constantly, and the difference decides whether the result is editable. Interleaving keeps every source discrete: four mono files become a four-channel file, and an editor can still mute the lav and keep the boom. Mixing sums the sources into fewer channels, and once the boom and the lav share a channel there is no way back.

This page interleaves. If what you actually want is a fold-down to one or two channels, use stereo to mono for summing, or the surround downmixer for a LoRo fold of a surround bed.

Channel order and channel names

Channel order is a delivery decision, not a detail. Most post workflows expect the stereo mix on channels 1 and 2 with isos below it, in the same order every take, so an editor can build one track layout and reuse it for the whole shoot. Drag the rows until the list matches that sheet before exporting.

The name on each row is written into the WAV as that channel's track name, which is what a DAW or an inspector reads back when the file is opened. Give channels the names people downstream use, not the filenames your recorder produced. Poly WAV channel order: what track 1 actually is covers the conventions in detail.

Compatibility: what has to match

Sample rate

The first file in the list sets the rate. Files recorded at another rate are resampled to it during export, which is a real conversion, so it is better to fix the mismatch at source when you can. Need the whole set moved first? Convert sample rate and bit depth.

Bit depth

Also taken from the first file, unless you override it in the export settings. Merging 24-bit sources into a 16-bit export requantises them; leaving the setting on Source keeps the depth the sources already had.

Duration

Channels shorter than the longest one are padded with silence at the end. That is safe only if every file starts at the same instant: a file that is late at the head will stay out of sync for the whole take, and padding will not fix it. The tool lists every mismatch before you export so you can check.

How to merge mono WAV files

Drop all the mono files at once; they appear as a channel list in load order.
Drag the rows to set channel 1, 2, 3 and so on.
Rename each channel to the mic or role it carries.
Read the compatibility notice: it names any file that differs from the first.
Audition the assembled multichannel file in the player.
Name the output, keep the settings on Source, and export the interleaved WAV.

Technical specifications

Input

Mono WAV, AIFF, MP3, M4A, FLAC, OGG
Up to 12 sources per merge
Up to 500 MB per file free, no cap on Pro
Multichannel sources are rejected, not flattened

Output

One interleaved multichannel file
WAV free; AIFF and MP3 on Pro
Sample rate and bit depth default to the first file
Channel names written into WAV exports
Per-channel trim, 0 dB by default

Need to go the other way? Split a multichannel WAV back into mono files.

See how it works

How to Merge Mono Audio Files into One Multichannel FileWatch the step-by-step tutorial and combine several mono files into one multichannel file.Watch the tutorial →

Your audio stays on your device

Decoding, processing and export all run in your browser: compressed formats are decoded with the Web Audio API, and WAV, AIFF and MP3 files are written by JavaScript in the page. Your audio is never uploaded to our servers. Only anonymous page analytics and, if you sign in, your account and payment details go online.

Frequently asked questions

How do I combine mono WAV files into one multichannel file?: Drop all the mono files on the merger above, drag them into the channel order you want, then export. Each source file becomes one channel of a single interleaved WAV; the first row is channel 1.
What is the difference between merging and mixing?: Merging is interleaving: every file keeps its own channel and its own level, nothing is summed. Mixing would fold several sources into a shared channel. This tool only interleaves, so a 5-file merge always produces a 5-channel file.
Do the files have to be mono?: Yes. A stereo or multichannel file is rejected with a message telling you how many channels it has. Split it into mono first, then bring the parts back here.
How many files can I merge at once?: Up to 12 mono sources in one poly file. Individual files above 500 MB need Pro.
Do the files need the same sample rate, bit depth and length?: Ideally yes, and the tool flags every file that differs from the first one before you export. If you export anyway, the first file sets the sample rate and bit depth for the whole export, other rates are resampled to match, and channels shorter than the longest are padded with silence at the end.
Will merging change my levels?: Not unless you ask it to. Each channel is written at its original level; the per-track trim next to each row is the only gain applied, and it defaults to 0 dB.
Can I set the channel order?: Yes, and it is the point of the list. Drag rows until the order matches the track sheet your editor expects, for example mix on 1 and 2 followed by boom and lavs.
Are the channel names kept?: The name shown on each row is written into the exported WAV as that channel's track name, so the file arrives self-describing. Names are edited inline before export; AIFF and MP3 output carry no track-name field.
Is this the same as building a PolyWAV?: Yes in substance. A poly WAV from a field recorder is an interleaved multichannel WAV, which is exactly what this produces. Keep the channel order consistent with the recorder's convention if the file has to sit alongside real poly takes.
Are my stems uploaded?: No. Decoding and interleaving happen in your browser and the merged file is written straight to your downloads.

Related audio tools

Split a PolyWAV back into mono tracks Reorder the channels of an existing file Multichannel Audio Splitter Check sample rate, bit depth and channels Version française

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