Dual Subs set up advice


Can anyone give me some advice on best practice to run dual subs? I have two Martin Logan Descent i subs for a strictly two channel system with ML Prodigy mains.

My options are:
Speaker level in
RCA in (sub has both left and right in for single sub use)
Balanced XLR (LFE)in (only one XLR in)

I am running the Sonic Frontiers Line 3 which has both balanced and SE outputs.

As of now, I am running them from the 2nd post on my Krell 300M amps but was wondering if it would be just as well to run SE (rca) left out from preamp to left sub in and vice versa for the right. Or, go balanced #2 outs (balanced #1s used for amps) to the single (XLR) LFE in on the subs.

Thoughts opinions?

NAK8
nak8
another comment unrelated to the hook up method. Have you ever tried running the subs at different locations? I was at a friends house, he was running ML CLS mains and had two subs. One sub was in one of the front corners of the room. The second sub was placed all the way in the back of the room - middle/center. The depth of the sound stage was amazing. If your cables are long enough, give it a shot and see what you think.
You had better have a large room if you want to try ML Descenti subs in different locations, not to mention moving them around.
I have only one word which can describe moving SoundLabs once they are spiked - HERNIA!
Scousepasty, so to understand you... you feed from the high voltage speaker terminal to the low voltage RCAs on the subs? Or do you mean you run RCAs to the amp and you Y off them to the RCAs on the subs? Or...from the high voltage speakers post you run to the speaker level in on the subs...

At the moment, I run them like the the last option via high voltage but thought it would be just as well to run RCA from the preamp.
I have dual NHT subs, and related NHT SS dual amps. I have three systems, each with separate pre amps. One has dual amps outs, one a sub out, and one with only tape outs. I route all of the outs to a Chase RLC remote controlled unit as a switcher that goes to each of the NHT amps. I do not use the NHT amps to feed the three different sets of speakers that I use individually, all driven by tube amps. Since the line out of each pre amp is different, the Chase unit's remote is used to adjust the output of the NHT sub amps. Works well, gives a lot of flexibility. For WAF purposes, each sub is in a front of the room corner, but I have been testing various other placements. Nothing finalized yet.
I use an Audio Control Richter Scale crossover for a similar setup. It has a built in EQ for the bass level and this helps a lot in balancing the setup. It operates at pre-amp level only however.