In an attempt to get things back to compression, I'll repost my earlier question:
I've been meaning to reply to you on this but have been caught up in work madness and haven't been able to do it so far.
There isn't really much wrong with the way you're doing it assuming that the comps are only kicking in on really loud bits (i.e high threshold). The issues creep in when the comps are active most of the time, and/or the ratio is getting up there. Also assuming that this approach serves your FOH needs as well.
What I suggested in my earlier post was to remove per channel compression for monitors to preserve the singer's full dynamic range on stage but to add limiting further down the chain to protect the drivers in the wedges. In that instance, you'd want to set the comp up with a high ratio (20:1 or more) and set the threshold so that it kicks in right at or just before the speaker's maximum safe SPL. If your power amp is well matched you can set the limiter up to kick in right below the amp's clip point. So until you're getting into the physical limits of the monitors, there is no compression active. Does this make sense?
If you're using (most) powered speakers or any kind of processed system you probably already have that protection.
As for effects in monitors, there aren't really any hard and fast rules but in general they aren't particularly desirable for most singers and in my experience, most seasoned vocalists do not want them in their monitors (we're assuming wedges here, IEMs are a different story) unless in an extremely dry and controlled environment. Once again, in my experience it's usually the greener singers that want effects in their wedges and in my opinion, that's actually detrimental to best performance, though they may not think that.
Trying to make monitors sound like the FOH is very often an exercise in frustration and typically results in the musicians not hearing themselves as well as they could if the monitors were set up differently. It's a big mistake that green (and sometimes experienced) musicians and monitor engineers often make along with checking monitors without the FOH on. Those wedges that sound nice and smooth in isolation are going to disappear once the FOH kicks in.
All that said, there are always exceptions to every rule and as a sound engineer, I don't consider it my place to dictate how someone's monitor mix sounds and I will do whatever is necessary to make the musicians comfortable. I'm not shy to offer a bit of advice, though and there have been lots of situations over the years where my suggestion to EQ a monitor mix a bit shy of low end and a bit strident in the upper mids, and to dump the effects have resulted in singers with reputations of being hard to mix monitors for being very happy with theirs when set up that way. And some where that approach did not work too.
