hello. so, I'm beginning the process of upgrading my gear setup, and one of those stages is getting a proper compressor. I currently use a Boss CS-3 Compressor/Sustainer pedal to do my compressing for the top end (I run two outputs via Chris Squire/Billy Sheehan/John Paul Jones style), and this pedal only compresses the top end. I think I've figured out lately that my sound getting a bit muddy could be cured with a bit of compression as well. so, I'm looking for a dual channel rackmount compressor to run the high and low side through. a question I have, though, is a compressor also a "compressor/sustainer" and the CS-3 is marked? like, does the "sustainer" part come from the compressing of the signal? or is this a special feature I'll have to look for when looking for a rackmount compressor. and also, I've only heard of a couple of brands, but what would some of the differences be between an Alesis 3630 and an Ashly CLX 52? http://www.alesis.com/3630 http://www.ashly.com/clx-52compressor.html or would anyone recommend anything else? aside from the Boss CS-3 pedal I've been using, I'm completely new to this compressor business.