How do I check if my mix is mono compatible?

Drop it here: it shows the loudness lost when summed to mono and the share of the song with the sides out of phase.

What correlation is good?

Above 0 for most of the song. Moments dipping below 0 are common in wide mixes; long negative stretches mean something cancels.

No. It's measured in your browser and never leaves your device.

Mono Compatibility Check

Phones, smart speakers and many venues play one channel. This check folds your stereo file to mono and shows how much loudness it loses, whether the sides work against each other, and whether the file is really mono. Measured in your browser — nothing is uploaded.

Music: a wide mix should still hold up in mono.

Measured entirely in your browser — your audio is never uploaded anywhere.

Your audio is decoded and measured entirely in your browser. It is never uploaded or stored by CAPTD and never leaves your device.

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Spotlight, CAPTD's workspace for promoting your work, is part of CAPTD's paid plans — see pricing.

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How to use this

What it does

Measures the left and right channels' correlation over the whole file and second by second, then the BS.1770 loudness of the mono fold-down ((L+R)/2) against the stereo loudness. It also compares the two channels' loudness and spots files whose two sides are identical.

What you'll need

A stereo audio file: WAV, FLAC, AIFF, MP3, M4A.

Steps

Pick Music or Speech.
Drop the file on the box.
Read how much it loses in mono and whether any passages cancel.

Reading the result

Correlation near +1 means the channels move together (mono-safe); near 0 they're unrelated (a wide mix); below 0 they work against each other and cancel in mono. Loudness lost in mono is measured so a mono mix loses 0 dB.

Tips

Check the low end first: bass and kick should be centred and in phase.
Stereo wideners and some reverbs are the usual cause of mono cancellation.
For podcasts, a mono export is perfectly fine — and half the file size.

Learn more

What is mono compatibility?

A stereo mix is mono-compatible when it still sounds right with both channels summed into one. Sounds that are out of phase between the sides cancel when summed, so a part can get thinner or disappear on a phone speaker.

Correlation shows how alike the two sides are, from +1 (identical) through 0 (unrelated) to −1 (one is the other upside down).

Why creators use it

A large share of listening happens on one speaker: phones, smart speakers, laptops, shops and clubs. A mix that collapses in mono loses impact exactly where many people hear it.

Common mistakes

Widening the whole mix. wideners often push the sides out of phase; use them on a part, not the bus.
A phase-flipped mic. two mics on one source, one with reversed polarity, cancel in mono.
Thinking stereo podcasts are better. for speech, mono is standard and safer.

FAQ

How do I check if my mix is mono compatible?: Drop it here: it shows the loudness lost when summed to mono and the share of the song with the sides out of phase.
What correlation is good?: Above 0 for most of the song. Moments dipping below 0 are common in wide mixes; long negative stretches mean something cancels.
Is my file uploaded?: No. It's measured in your browser and never leaves your device.