Multiband EQ - Grey line on the back?

FMOD Studio
1

Hi !

Hope you’re all good.

I have a question about the multi band EQ. What’s the purpose of the grey line in the back of the red line ? It’s looks like kind of an opposite curve ; but not always.

Some help for lightning my brain ?

Thanks for the help,

Respects,

Martin,

2

The grey background line represents phase response of the filter.