A general rule would be to start with a ratio of 3:1, a threshold of -10 or 20, and a medium fast attack and medium release. That's a generic setting that you can then tweak to suit the task at hand. A vocal may only need gentle limiting, like high ratio(4:1 to 8:1), high threshold(-10 to -5 , etc. You don't have to squash it(high ratio, low threshold, etc.), unless your looking for that tough aggresive sound. Too slow of an attack and you won't catch the peaks.Too fast a release and the compressor grabs the signal, then lets go, resulting in pumping and breathing(again, only useful if you want that very compressed sound).
I'm not familiar with that piece of gear, but I do know that some onboard digital compressors are a little generic and utilitarian.You buy a box that is an all in one studio in a box and the effects might be lame or the mic pres ain't too happenin or whatever. They are appealing in some ways and kinda cool in concept, but for the money they cost, you can't expect the compressors to win awards for being sweet sounding and precise instruments.
Some software plug in ones are wonderful, like the Waves, Focusrite, Drawmer, GML, and others. I used to work on a pair of Panasonic DA7 digital consoles and liked the onboard compressors ok. It was nice having one on every channel, plus on the 2 track bus. Very handy. I also like the ones in
the Yamaha 02R, the Mackie ain't no slouch either. I guess if you ain't diggin the ones you got, getcha some cool outboard ones. Joe Meek SC2, FMR Audio RNC, and
Drawmer MX30 are all affordable and inspiring tools, not dull lifeless utilities.
