I don't consider myself a pro or guru but here's a suggestion that may help.

As you play the vox "sweep" the eq at a fairly high db through the frequency range until you hear the freq where it sounds the worst - could be really honky around 1k or elsewhere. Then narrow cut - bring down the eq there. You might also try sweeping again to hear which freq sounds best and boost slightly. Trial and error. Just go back to the original some with your eq disabled to compare and keep your perspective.

Maybe that will help.

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