Need some audiogon expertise

Great points made above. Speaker positioning is generally a good starting point. Your room dimensions aren't bad so that shouldn't cause too many problems. I assume you have a fairly standard room -- i.e., not too many large openings into other areas, not too many hard surfaces, a decent amount of carpeting and cushioney (is that a word?) furniture. If not, then start with the room itself, especially if it seems like the speakers are throwing out decent bass if you put your ear (or meter) right next to the woofer.

I also assume that the lean bass comes across whether you use your tuner or cd player so I wouldn't look for answers there, at least not right away. If it's easy to borrow a decent preamp, you might want to switch that out to see if it makes a difference (by the way, as Sean suggests, it may be the amp/preamp cable rather than the preamp itself if the borrowed preamp sounds better -- i.e., impedence/inductance/capacitance matching may be off). Finally, you might want to borrow other speakers and see if that makes a difference. If so, then you may have some worn parts. Visually inspect the woofer cones for tears or cracks -- if they are there, replace the cones. If everything still looks good, consider replacing the capacitors in the cross-overs as a final last resort once you determined it is the speakers.

Sean, whattafool I always mistake Aragon for Adcom i.e. finger with ...&^%$% if you know what I mean...:-)

I think you nailed it with amp/pre synergy since the output impedance of L1 is arround 2k.

FWIW if you system has an upper midrange emphasis it might lead you to believe you have reduced bass or midbass (a general lack of warmth). A couple of your components are not (IMHO) tilted toward warmth and are neutral at best, but should not cause a lack of bass. I agree with previous comments that you should investigate proper room placement of the speakers and the listening position, using a RS meter and a good test CD. If you have not already do so you should check out the various theories for room placement, such as Cardas. Rives has a nice web site. Both are good for some begining understanding and as starting points.

Moving your speakers closer to the back wall will ad some boundary reinforcement to the low end. But you could muck up the low mids and imaging. The better solution is to move the listening position so that you are sitting as close to the back wall as possible. Antinodes (the part of the waveform with the highest amount of displacement) occur at room boundaries. As long as you sit with your head no further than 1 1/4 feet from the back wall, the bass will be at a higher amplitude, and the mid to high frequency reflections from the back wall will be so short, that your brain won't be able to distinguish them from the direct sound. If you want more info I think AudioPhysics has some info on their website regarding this monitoring scheme.

you'll get much more of an effect (you can expect ± 10dB/spl below 200Hz in some rooms) with speaker/listening position placement than you ever will with cables or electronics (other than an EQ). Save your money, take a little time, and if that doesn't work, then think about altering your equipment.

I have the RM 40's and so does a friend. He used the TACT device - very expensive and somewhat complicated to get a fuller and more controlled sound. I had a thin sound in my room and tried the Peavey Kosmos - it did the job. Say what you want but everything sounds thin without it. I also have one in my Focus 20/20 system. It can be bought direct with a 30 day trial. All this other advice is very good but the Kosmos cuts out a lot of the trial and error and makes a huge difference and you can put your speakers where you want in the room.