
To my best recall (busy weekend) I think I only did the review of the MDX2600, rather than a separate functions list - but then again...
Incidently, I'm now about to start using a 2nd MDX-2600 on my setup, PURELY as a stunningly good Auto-music-ducker for when I want the music to subtlely dip automatically, whilst I'm talking on the mic, or radio mic - out in the audience.
The MDX 2600, as well as having connectors for music coming in, and music going out, has a feature called Sidechain which has a mono in, and a mono out for a 2nd sound source eg: Mic. When the 2600 detects mic signals over a certain level in its sidechain input, it fades the music away (adjustable speed) to an adjustable lower level as you talk, then...when it detects the mic signal level is lower (eg: you've stopped talking) it fades the music back up to the previous volume again at an adjustable speed. eg: takes .5 of a second to dip the music when you start talking and takes 1.5 seconds to fade the music back up after you stop talking.
I use one on my disco set-up mainly to compensate for the standard DJ problem of hearing threshold shift - eg: where, after a couple of hours in a venue, the DJs hearing makes him think that the volume needs to go louder, then an hour or so later that it needs to go louder still etc... only evident when you walk out of the room for a couple of minutes, then walk back in and think "Gah! its loud in here." and turn the volume down again.
As far as your settings of your MDX2600 goes, I'd suggest that you stick everything on bypass first - then only take things off of bypass as you adjust them.
Start with the Peak Limiter - this is a crass'n'brash "last resort" (A bit like Weymouth

) . Consider the peak limiter to be there so that if all else fails (to keep the levels nice in a subtle fashion) the Peak limiter will BASH the signal levels over the head to stop them going past the peak limit that you set (the audience and you will both notice when the peak limiter kicks in, if it has to - the sound will be "strained"). Set this to the highest maximum level that you want the signals to ever reach, and never exceed.
Your compressor settings however, should mean that the levels are always dealt with neatly, discretely and almost inaudibly before the levels ever reach the levels where the peak limiter ever cuts in. To begin with, set your mixer up so that the signals are all iquite loud, just bouncing very (very, very) occasionally into the red, then try using the AUTO button on the Compressor section and adjust the Threshold rotary, until the signal meters on the compressor limiter are showing bouncing green LED only...the moment you see RED LEDS, it means that the compressor section of the 2600 is having to actively apply compression to the signal...if you get RED LEDs, turn the Threshold setting until only the green LEDs bounce.