# Check your mix in mono
Source: https://docs.aden.space/docs/help/your-music/audio-analysis/mono-check

See and hear what your mix loses when a club system, phone or radio sums it to mono.
Club systems, phone speakers and most Bluetooth boxes play in mono. Anything out of phase between left and right disappears, and you won't hear it on headphones. The mono check shows what survives.

## Run the check [#run-the-check]

1. Play the version and click the loudness readout above the waveform to open the EQ panel.
2. Under the EQ, press **Run mono check**. It takes a few seconds on a long master.
3. Click the verdict for the details: correlation, how much level the mono sum loses, stereo width, low, mid and high bands, and a timeline with the worst moment.
4. Flip the **Mono** switch while it plays, or use the jump to the worst moment, and listen.

The meter tells you how much collapses. Your ears tell you whether it matters.

## Read the verdict [#read-the-verdict]

| Verdict              | What to do                                             |
| -------------------- | ------------------------------------------------------ |
| **Sums cleanly**     | Nothing.                                               |
| **Wide, still sums** | Pull back the stereo widener on the master.            |
| **Thins in mono**    | Something under 250 Hz is off centre. Centre the bass. |
| **Cancels in mono**  | A channel is flipped. Check the stems.                 |

A mono level drop over about 1.5 dB is worth a look; 3 dB is a problem. Fix it in your DAW, upload the new version, and check again.

The result is saved with the version once you've listened in mono. Versions that thin or cancel show a badge in the versions list, so a problem master is visible before anyone opens it.

## Related [#related]

* [Shape playback with the EQ](/docs/help/your-music/audio-analysis/eq)
* [Get feedback on your mix](/docs/help/your-music/audio-analysis/track-feedback)