Free tool
Mono compatibility checker
Drop a mix on the scope and press Mono to hear what the fold takes away. The readings underneath use the same maths as MS Field: correlation and mono loss per band, and the bass frequency that cancels first.
Drop a mix here
Your file stays on this computer. Nothing is uploaded or stored.
A taller bar loses more in mono. Click or drag to jump there.
Drop a mix to see the readings.
| Band | Correlation | Mono loss |
|---|---|---|
| Whole mix | — | — |
| Low · 20–200 Hz | — | — |
| Mid · 200 Hz–2 kHz | — | — |
| High · 2–20 kHz | — | — |
Bass Check
Mono loss per third-octave below 200 Hz, in dB. Greyed rows are too quiet to judge.
- 25—
- 31.5—
- 40—
- 50—
- 63—
- 80—
- 100—
- 125—
- 160—
- 200—
Anything your browser can play: WAV, MP3, AAC and FLAC in every current browser, AIFF in Safari. Up to 200 MB. A four-minute song takes a few seconds to measure.
Reading the numbers
- Correlation
- +1 means left and right carry the same signal. 0 means they have nothing in common, which is what a hard-panned sound or a wide reverb reads. Below 0 they work against each other and cancel when summed.
- Mono loss
- How much level a band loses when left and right are summed. 0 dB is a mono source. −3 dB is two unrelated channels at the same level, normal for a wide pad or doubled guitars. Past that, something is cancelling.
- The colours
- Green, amber and red use the thresholds from MS Field. The low band is judged more strictly, because phone speakers and club subs play the bass in mono.
- The Mono button
- Mono plays (L+R)/2 on both speakers. A centred sound keeps its level and a wide one drops. It isn't level-matched: the drop is what you're listening for.
- Bass Check
- Ten third-octave rows from 25 to 200 Hz. The check names the row losing the most and the frequency to fold below, the way Bass Check in MS Field does.
More on mono
Mid/side metering plugin
The same readings, live in your DAW
MS Field shows these numbers while the track plays, per band and per bass row, next to a mid/side spectrum. It doesn't touch the audio.
MS Field —