You need to buy the lil HP/LP modules and then you can make your own sip chips for each frequency based off resistor value AFAIK - or buy the chips off ebay or call up xtant/mtx. Basically, a PITFA.
This works on the X series, I would expect the M series to be the same
Steps to creating a custom crossover frequency sip
1. Choose a crossover frequency from the chart and note the
corresponding sip code.
2. Translate sip code into a resistor value.
3. Load 6 - 1/8th or 1/4 watt resistors into the sip socket isolating the leads.
That only works if you have the crossover circuitry on your amp :P
The X series has a crossover for which you can adjust the frequency...however, the m series does not.
You need the modules for it to do anything.
Speaking of which...i should sell my Parametric Module i have. Was gonna use on my 2200i, but then blew the input stage by touching the module input pins with a screwdriver while it was on (trying to adjust something)...damn open circuit board.
Otherwise i also love the Xtant amps.
ON a side note, from the russian mobile magazine (i forget it's name, AutoByte???) The A series actually puts out more power and at less distortion. somewhat based on the same board too. So the A4004, and A2002 are also very good. (compared to 404m and 202m which i run). Both are excellent and the balanced input circuitry is a godsend which eliminated all my engine whine.
I use the 202m for my seas tweets and the 404m bridged to my rs180's
ya...i got A4004, then sold for Avionixx 600.4, sucked (noise and problems)...warranty replaced with 800.4 OK i guess but not as good...then got the A4004T (titanium silver one...nice)...worked great...then added 202m for tweets, then got matching 404m and sold a4004...meanwhile i always bought them for $100us and sold locally for $175Cdn...so made money always. Xtant is truely a good brand and i think even their new stuff is fine although having been bought out. (still have the balanced input and also a good amplifier circuit overall)...although maybe i shouldn't hype them up as the prices will rise on ebay.
Excuse the newbness but are specific crossover chips still required even if using the 404m to power an active setup, or will the HU take care of everything in that case?
The chips don't alter amplitude or anything else if they aren't installed. The pins have a jumper on them that allows them to bypass any signal altering. The function of the amp is to change the amplitude of the signal.
The amp changes the amplitude but the crossover chips will allow different frequencies to pass or be blocked. It's a little more complicated than what you've described but you're on the right track.
xtant 404m
but are specific crossover chips still required even if using the 404m to 
Linear Mode
