How do I downmix 5.1 to stereo?

Drop the 6-channel file on the tool above. Each channel is given a role (L, R, C, LFE, Ls, Rs) from its metadata and the SMPTE order, and you can reassign any of them. Check the fold in the preview, trim the faders if it peaks, then export a stereo file.

What downmix does this tool actually perform?

A LoRo matrix fold. Lo = L + 0.707 × C + 0.707 × Ls, Ro = R + 0.707 × C + 0.707 × Rs, with each channel's own fader applied on top. It is a straight sum with fixed coefficients; no phase encoding, no limiting, no loudness normalisation.

Is this LoRo or LtRt?

LoRo only. LtRt folds the surrounds with a phase shift so a matrix decoder can recover them later; this tool does not phase-encode anything, so the output is a plain LoRo stereo pair and should not be labelled LtRt on a delivery.

What happens to the centre channel?

It is split equally into both legs at 0.707 (-3 dB), and the centre fader starts at a further -3 dB, so by default the centre arrives about 6 dB below unity in each leg. Dialogue lives there, so audition the fold and raise or lower that fader to taste before exporting.

What happens to the surround channels?

Ls and Lsr go to the left leg, Rs and Rsr to the right, at the same 0.707 coefficient and the same -3 dB default fader. They are not folded into the opposite leg and they are not phase-shifted.

Is the LFE included in the downmix?

No. A channel assigned the LFE role contributes nothing to either leg, which matches normal LoRo practice: the LFE is an effects feed, not a bass channel. If you specifically want that content in the stereo file, give the channel the C, L or R role instead.

Which surround layouts are supported?

Any file with 3 or more channels. LCR, quad, 5.0, 5.1 and 7.1 are auto-mapped from the SMPTE order and the channel names in the file; anything else you assign by hand with the per-channel role selector.

Will the downmix clip?

It can, because summing channels adds energy. The tool measures the peak of the folded pair live and warns you with the exact dBFS value when it goes over 0. Nothing is limited automatically: you trim the faders and re-check.

Does this produce a broadcast-compliant deliverable?

It produces the stereo fold; it does not measure or correct loudness. If your delivery specifies a LUFS target, measure and adjust the exported file separately.

Are my files uploaded?

No. Decoding, the matrix and the export all run in your browser, and the stereo file is written straight to your downloads.

Surround downmixer

Surround to Stereo – 5.1 and 7.1 LoRo Downmix

Fold a 5.1 or 7.1 mix down to a stereo LoRo pair with a fader on every channel, a live preview of the actual fold and a peak check before export. The matrix is printed, not hidden, and the file never leaves your browser.

1st conversion free
No installation
No plugin
Files stay local

Drop your surround mix

5.1, 7.1, quad or LCR. WAV, AIFF, MP3, M4A, FLAC, OGG. Folded to stereo LoRo in your browser

Browse files

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

Watch how to downmix 5.1 to stereo

What this tool does for you

Fold a 5.1 or multichannel mix down to a stereo LoRo master
Adjust the contribution of centre, surrounds and LFE with per-channel gain
Audition the fold before exporting, so dialogue level is checked not guessed
Export WAV, AIFF or MP3 at your chosen rate and depth
Everything runs in your browser. Files are never uploaded to a server.

How it works

01. Drop your surround mix
Channel roles are read from track names and the SMPTE order.
02. Balance the fold
Trim C, LFE, surrounds and L / R, and listen to the stereo preview.
03. Export the stereo file
WAV, AIFF or MP3 at the rate and depth you choose.

LoRo downmixing without a dub stage

What LoRo means

LoRo, left-only/right-only, is a straight matrix fold: left plus centre plus left surround becomes the left output, right plus centre plus right surround becomes the right. Centre and surrounds are attenuated, classically by 3 dB, so the sum does not overload. It differs from LtRt, which encodes surrounds with phase information for a matrix decoder.

Watch dialogue and the LFE

Dialogue lives in the centre channel, so the centre coefficient decides whether your downmix is intelligible on a laptop. The LFE is usually excluded entirely: it is a separate low-frequency effects feed, not a bass channel, and folding it in muddies the result and eats headroom.

Check the level after the fold

Summing six channels into two adds energy. Always look at the peaks after the downmix, and re-check integrated loudness if you are delivering to a broadcast or streaming spec, because the stereo version has its own target.

Professional use cases

Post-production

Create the stereo deliverable that sits alongside the 5.1 master in a distribution package.

Video editing

Turn a surround mix into a stereo review copy that plays properly on any laptop.

Sound editing

Test how a surround design holds up when the audience hears it in two channels.

Downmix 5.1 to stereo

A surround bed carries six discrete feeds. A stereo deliverable carries two. The fold down decides how the four channels that have no stereo equivalent are distributed, and that decision is what makes a downmix good or unusable.

INPUT (5.1)          MATRIX                      OUTPUT (stereo)

  L  ────────────────  ×1.0  ───────────────────▶  Lo
  C  ────────────────  ×0.707 ──────────────────▶  Lo + Ro
  Ls ────────────────  ×0.707 ──────────────────▶  Lo
  R  ────────────────  ×1.0  ───────────────────▶  Ro
  Rs ────────────────  ×0.707 ──────────────────▶  Ro
  LFE ───────────────  (not folded in)

How the channels are combined

Source role	Into Lo	Into Ro
L	×1.0	—
R	—	×1.0
C	×0.707	×0.707
LFE	not folded in	not folded in
Ls	×0.707	—
Rs	—	×0.707
Lsr (7.1)	×0.707	—
Rsr (7.1)	—	×0.707

On top of these fixed coefficients, every channel has its own fader from -24 to +12 dB. The tool starts C and the surrounds at -3 dB and L / R at unity, so the default fold is a conservative one; the exact matrix in use is printed under the channel list.

Centre, surrounds and LFE

Centre channel treatment

The centre is sent equally to both legs, so it stays phantom-centred in the stereo image. Since dialogue lives almost entirely in the centre on a film mix, this single fader controls whether the downmix is intelligible on a laptop or buried under music and effects. Audition it against the loudest music cue in the reel, not against a quiet scene.

Surround channel treatment

Left surrounds fold into the left leg only, right surrounds into the right leg only, at -3 dB from the matrix. Reverb and ambience therefore move forward into the stereo image. On a 7.1 bed the rears (Lsr, Rsr) are treated exactly like the sides.

LFE treatment

A channel assigned the LFE role is excluded from the fold. That is deliberate: the LFE is a separate low-frequency effects feed, usually mixed with +10 dB of in-band gain, and summing it into a stereo pair muddies the low end and eats headroom. If your particular mix genuinely needs that content in stereo, assign that channel the C, L or R role and set its level yourself.

LoRo, LtRt and plain stereo folds

LoRo (left only / right only) is a plain sum: each surround channel goes to its own side, the centre goes to both, and what you hear is what you get. It is the safe fold for review copies, streaming stereo versions and any situation where nobody downstream will run a decoder.

LtRt (left total / right total) encodes the surrounds with a phase shift so a matrix decoder can pull them back out into a surround field. It sounds different when played flat, and it should only be labelled LtRt if it was genuinely encoded that way. This tool does not phase-encode, so its output is LoRo.

A generic stereo downmix in an NLE or media player is usually LoRo with unpublished coefficients, which is exactly the problem: you cannot tell what happened to dialogue level. Doing the fold deliberately, with the matrix written down, is the point of this page. The LoRo downmix explained covers the reasoning in more depth.

When you need a stereo downmix

A distributor asks for a stereo version alongside the 5.1 master.
A review copy has to play correctly on laptop speakers and headphones.
A festival or platform accepts stereo only, and the mix exists in surround.
You want to check that a surround design still reads when the audience hears two channels.

Before folding, make sure the channel roles are what you think they are. If the file arrived in film order rather than SMPTE order, either reassign the roles here or reorder the channels first with the channel mapper.

How to use the downmixer

Drop a file with 3 or more channels: LCR, quad, 5.0, 5.1 or 7.1.
Check the auto-assigned roles against your channel list and correct any that are wrong.
Play the preview: it is the actual folded stereo pair, not the source.
Trim the centre, surround and L / R faders until the balance is right.
Watch the clipping warning; if it appears, pull the faders down rather than exporting hot.
Pick the output format, rate and depth, name the file and export.

Technical specifications

Input

WAV, AIFF, MP3, M4A, FLAC, OGG
3 channels minimum; LCR, quad, 5.0, 5.1 and 7.1 auto-mapped
Up to 500 MB free, no cap on Pro
Roles auto-detected from track names and SMPTE order

Output and processing

2-channel LoRo, channels named L and R
WAV free; AIFF and MP3 on Pro
Sample rate and bit depth default to Source
Fader range -24 to +12 dB per channel
Peak measured before export, no automatic limiting

See how it works

How to Downmix 5.1 Surround Audio to Stereo — No DAW RequiredWatch the step-by-step tutorial and fold a 5.1 surround mix into a stereo deliverable, channel by channel, in your browser.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 downmix 5.1 to stereo?: Drop the 6-channel file on the tool above. Each channel is given a role (L, R, C, LFE, Ls, Rs) from its metadata and the SMPTE order, and you can reassign any of them. Check the fold in the preview, trim the faders if it peaks, then export a stereo file.
What downmix does this tool actually perform?: A LoRo matrix fold. Lo = L + 0.707 × C + 0.707 × Ls, Ro = R + 0.707 × C + 0.707 × Rs, with each channel's own fader applied on top. It is a straight sum with fixed coefficients; no phase encoding, no limiting, no loudness normalisation.
Is this LoRo or LtRt?: LoRo only. LtRt folds the surrounds with a phase shift so a matrix decoder can recover them later; this tool does not phase-encode anything, so the output is a plain LoRo stereo pair and should not be labelled LtRt on a delivery.
What happens to the centre channel?: It is split equally into both legs at 0.707 (-3 dB), and the centre fader starts at a further -3 dB, so by default the centre arrives about 6 dB below unity in each leg. Dialogue lives there, so audition the fold and raise or lower that fader to taste before exporting.
What happens to the surround channels?: Ls and Lsr go to the left leg, Rs and Rsr to the right, at the same 0.707 coefficient and the same -3 dB default fader. They are not folded into the opposite leg and they are not phase-shifted.
Is the LFE included in the downmix?: No. A channel assigned the LFE role contributes nothing to either leg, which matches normal LoRo practice: the LFE is an effects feed, not a bass channel. If you specifically want that content in the stereo file, give the channel the C, L or R role instead.
Which surround layouts are supported?: Any file with 3 or more channels. LCR, quad, 5.0, 5.1 and 7.1 are auto-mapped from the SMPTE order and the channel names in the file; anything else you assign by hand with the per-channel role selector.
Will the downmix clip?: It can, because summing channels adds energy. The tool measures the peak of the folded pair live and warns you with the exact dBFS value when it goes over 0. Nothing is limited automatically: you trim the faders and re-check.
Does this produce a broadcast-compliant deliverable?: It produces the stereo fold; it does not measure or correct loudness. If your delivery specifies a LUFS target, measure and adjust the exported file separately.
Are my files uploaded?: No. Decoding, the matrix and the export all run in your browser, and the stereo file is written straight to your downloads.

Related audio tools

The 5.1 LoRo downmix matrix explained Fix the channel order before downmixing Split a poly WAV into mono tracks Check a file's channel layout Version française

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