How is this different from the phase meter?

The underlying measurement is the same normalised correlation of the two channels. The difference is presentation and extra readouts: this tool shows the classic broadcast needle with a segment history, while the phase meter adds a channel balance figure and describes the value in words.

What values should a music master show?

Dance and pop typically land between plus zero point three and plus zero point eight because wide synths and effects carry genuine side energy. A figure above roughly zero is generally safe for mono, and material hovering near zero is acceptable when the arrangement is deliberately spacious.

Why does a negative reading deserve attention?

Because it means the channels are partly inverted relative to each other, so a mono sum will cancel content instead of reinforcing it. Listeners on a phone speaker or a mono system then hear a quieter, thinner version of the mix, and the cause is usually a polarity flip rather than the arrangement.

Why only four history segments?

The history is meant to show the broad movement of the correlation across the file rather than every fluctuation. Four spans reveal a section that behaves differently, and a problem short enough to hide between two spans is better investigated by cutting that section out and measuring it on its own.

Does anything get corrected automatically?

No, this is a read-only measurement. If the value indicates a problem, the correction has to be made deliberately: test a polarity inversion, rebuild the sides, or return to the mix, then measure again to confirm the result improved.

Correlation Meter

You Might Also Need

Phase Meter

Check stereo phase correlation

Goniometer / Vectorscope

Visual stereo image analysis

Mid/Side Processor

Process mid and side separately

Channel Mixer

Mix and balance audio channels

Correlation Meter presents the stereo correlation of a file as a broadcast-style needle meter, with a running history across the recording. It measures exactly what the phase meter measures, but in the form a broadcast engineer would recognise.

What is Correlation Meter?

The bar runs from minus one on the left to plus one on the right with zero at the centre, and the filled segment shows where the file's overall correlation falls and how far it sits from the midpoint.

What the meter shows:

A wide meter track labelled at minus one, minus zero point five, zero, plus zero point five and plus one.
The overall correlation printed to three decimals, with a short interpretation next to it: highly correlated and mono-safe, dangerous anti-phase content, or a healthy stereo spread.
A running history in four segments, each showing the correlation for that part of the file so movement over time is visible rather than collapsed.
A note beneath the display giving the practical ranges that matter in delivery work.

The measurement is a normalised cross-correlation of the left and right channels, the same quantity a hardware correlation meter displays, with the result confined between minus one and plus one by construction. Reading it well is mostly about knowing what is normal for the genre. Broadcast masters are expected to keep the figure above roughly zero so that a mono television feed does not lose content, dance and pop records commonly sit between plus zero point three and plus zero point eight because their sides carry real energy, and very wide ambient or orchestral recordings can legitimately hover near zero where the two channels share little. A result that is consistently negative is the case worth acting on: it indicates that summing to mono will subtract rather than add. As with any averaged figure, the running history is what prevents an acceptable average from concealing a passage that goes badly wrong. The segment history serves the same purpose as a chart recorder attached to a hardware meter: it makes movement visible, so a file whose overall reading looks healthy but which swings sharply in one part can be identified rather than assumed safe. This is a mono-compatibility check first and a stereo width check second, and the two readings often disagree, which is useful information in itself.

Where the meter stops short:

The history has four segments only, so a short excursion inside a long passage may not appear.
Frequency dependence is not shown, so a bass-only polarity problem reads as one number.
A mono file cannot be analysed and is reported as unsupported.
The display is a measurement, not a processor: nothing is corrected here.
There is no time axis under the history, only segment numbers.
No logging or export of the values is offered.

Use it as the delivery check on a stereo master, and as a quick sanity test when a mix has been rebuilt from stems and the sides may have been reconstructed incorrectly. When the numbers need to be cross-referenced against the shape of the stereo image, the vectorscope shows the same material as a figure, and the phase meter gives the same measurement with an added channel balance figure.

How to use Correlation Meter

Drop a stereo audio file onto the panel; mono files are flagged rather than analysed.
Read the needle position against the labelled scale to place the file's overall correlation.
Step through the four history segments to see whether the figure moves during the file.
Check the interpretation line, and treat a consistently negative reading as the case that needs fixing.

When to use Correlation Meter vs related tools

Correlation Meter is the delivery check for stereo material that may be summed, so run it on any master headed for broadcast or for single-speaker playback. Phase Meter measures the same thing while adding a channel balance figure and a plain-language label, and Goniometer / Vectorscope shows the stereo field as a shape. Where the reading points at a rebuild, Mid/Side Processor and Channel Mixer are the tools that change the sides.

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