bitflipper
I'd think the 670 would be a bit of overkill for the master bus, but if it works it works! Try it on a vocal track or a drum bus. I've even used it on a picked acoustic guitar that was too spikey.
Hey bitflipper! I took your advice and took the FC70 off my master buss and put it on my drum buss and you were absolutely right! When it was on the master, I liked what it was doing to the drums but it was also robbing the entre mix of transients. By putting it on the drum buss only, it tames down the cymbals and tightens up the whole drum mix. I'm also able to get away with a bit more top end on the kick without it sounding overbearing. The whole drum mix sits better now!
Thanks again for your great advice! This really transformed my overall mix!