The correlation meter
indicates the degree of similarity or correlation
between the left and right channels.
When the audio in the left and right channels is similar, the meter draws towards the right. The extreme case is when the left and right channels are exactly the same, in which case the correlation is +1 and the meter would be positioned all the way to the right.
When the left and right channels are uncorrelated, or very different, the meter draws towards the left. The extreme case here would be for the left and right to be exactly out of phase, in which case the correlation is -1 and the meter would be positioned all the way to the left.
As the correlation meter updates, it "paints" a history to show the correlation of the left and right channels over time. Brighter regions indicate that the correlation meter has spent more time in that area. This provides you with a quick way to visualize the extremes of the phase correlation as well as the most common regions.
In general, most recordings have phase correlations in the 0 to +1 region. A brief readout towards the left side is not necessarily a problem but could represent a possible mono compatibility issue.
Note that as you apply greater multiband stereo widening or reverb width to your audio, the phase correlation will tend to draw more towards the left side, as the left and right channels will become "wider" or less similar.
You can perform a quick check of mono and phase compatibility by clicking on the Channel Ops box. This provides a menu that allows you to sum the output of Ozone to mono, invert the polarity of left or right channels, and swap left and right channels.
An additional meter for analyzing stereo spread is the Vectorscope, which you can learn about here...
Note: This help file is a quick reference for basic Ozone functions and controls. We have a separate "how to" guide that provides tips and techniques for mastering with Ozone. You can download this guide from http://www.izotope.com/products/audio/ozone/guides.html