Compression...

[tigeba]

All a limiter will do is keep your signal from clipping. It won't keep your audio from sounding poor when it slams the limiter. The way to do it is set your levels correctly.

 

[ullanta]

The only difference between an external limiter and the ones on the DVX is perhaps a little more flexibility in setting the limiting threshold. As the wise tigeba says, limiting is useful for totally unexpected loudness that occurs very rarely. If you set your levels right, you shouldn't reach the level where the limiter kicks in... it should only be there as an emergency measure. What this means is, if you're using just the DVX limiters, set the levels WITHOUT the limiter on so you make sure nothing is peaking (say, loudest parts at about 3 "blocks" down from peak in the DVX viewfinder), then engage the limiter to provide protection in case anything briefly gets louder than that.

Compression, on the other hand, can indeed be used creatively to improve your sound at recording time... but again, you really need to know what you're doing, and if you're not well-experienced at it, I'd suggest recording at safe levels without compression, then applying compression in post until you get the hang of it...