Hey man... I suck at the actual recording aspect of recording (tracking) ...so one of my best friends is the multiband compressor...I'm sure you have about 12 of them in Cakewalk if you're still using that. Anyway, you can mash the crap out of any frequency you want, and leave the stuff that's okay alone.
For example, for sibilance, you can usually SEE the "sss's" on the track, right? Well, this takes a little time, but it's always good to know where your most annoying frequencies are. If you have some kind of an analyzer, run it over JUST one of the S's and see where it's peaking. My sibilance is most annoying at 4550Hz and @5600hz. I just run a compressor over the vocal track with some ridiculous ration (10:1, or maybe 20:1...you know, stupid big compression), but then limit the frequencies that will be compressed to 4500-6000. Bingo, the rest of the track looks and sounds pretty much the same, but the "S's are tiny now. That's basically how a de-esser works...I don't like most de-essers, b/c they cut too wide a path...like 4000Hz-12000Hz - well, that'll kill ALL of an S all right, but some of the frequencies in an S are damned nice, lol...and if you squash all of them equally, then what you have is still a harsh S, it's just a harsh S that you can't hear anymore, lol. Plus, most de-essers only use ratios like 3:1, which makes sense b/c the frequency band is so wide that anything more would basically work to erase the S, lol.
As far as the threshold setting, that totally depends on how hot you recorded the track. Try -30 to start out with.
My point is, it depends on WHAT highs you're trying to kill. You posted about vocals, and you said "the highs are still getting killed", but then you talked about needing to tame them, so I'm talking about sibilance. Same principal, though, if you want to tame a high hat in a drum loop that's fixed and you can't turn down. Find out which frequencies of the hat are annoying you and compress the crap out of JUST those, leaving the rest of the hat volume in place so that you don't get that false "muted" or compressed sound.
Oh, and turn the damned gain down on your preamp, lol. That's the best way to record a dynamic vocal...get real close to the mic on the soft parts, belt out the loud ones by moving your head back...so that you're kind of self-controlling the output (from you), but leave yourself enough room so that you don't have to turn anything down during the tracking...besides, the hotter your preamp, the more hiss you're gonna' have on the track.
I'm sure you know all this; I just like to hear myself type.
I may get a lot of complaints on my recordings, but "the vocals aren't sitting right" has never been one of them, lol.
