Voxengo, the maker of the well-known SPAN spectrum analyzer, has put out yesterday a free correlation meter that features a side-chain input to compare specific signals.
https://www.voxengo.com/press/voxengo-c ... eased-339/
Voxengo plugins, in my case (Linux Mint 18 KDE) are running fine using wine-staging and linvst in both Bitwig and Mixbus32C (Ardour).
(Voxengo) Free Correlometer
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