Dave: Here are my impressions of the Acme vs Eden XST vs the Dr Bass 112 (3 way). First, let me tell you that, for my entire playing career (until this year), I've played through crap. So my ears are probably not as good at evaluating sound as others here.
As to high and mid detail, the Acme and Dr Bass stand above the Eden, for the reasons you'd expect. On this criterion, I like the Dr Bass a bit better than the Acme, partly because I like the high midrange sound out of the 6 in the Dr Bass more than the 5 in the Acme. The Dr. Bass has a more open, airier sound in the high-mid, where the Acme sounds a little too restrained to me. The tweeters are similar, but actually, the XST's tweet is the clearest of all - none are in the least bit harsh.
For low end, bear in mind I don't own a 5 string at this moment, so I can't speak to anything below E. The Acme and Eden sound similar - both go to the very bottom without breaking up or any unevenness. The Acme is little bit more solid at the same volume as the Eden, but drier sounding, where the Eden is more rounded and pleasant to my ears.
The Dr. Bass is loaded with an Eminence neomydium driver, making it the lightest of the 3 cabs at 44 lb (Eden is heaviest at 59 and the Acme weighs 50 lb.). The neo driver sounds much more open than the 10 pairs and I'd estimate the bottom (at similar volume and EQ) sounds a little less full than the bottom end on the Acme or Eden. However, with the bottom end tweaked up, the 12 is solid, does not break up on the low end (remember, it's a 4 string) and has a pleasant, rounded tone.
It may just be my taste, but I prefer the cleaner, more open sound of the 12, plus its added ability to project its full range over the 10s. Not everyone may share this bias. It's sort of like a super high quality 15, but with much more faithful tone production in the high-mid and none of the lag effect of the larger speaker.
The Eden is clearly more efficient than the Acme, but EQ's about the same. Both produce plenty of bass, but reaches the same volume at 11:30 that the Acme gets at about 12:30 on my power amp. The Dr. Bass sounds like it's operating at about the same efficency as the Eden.
I wish I could compare first hand to the Eden XLT, but don't have easy access to one.
Gary: The ELF processor is factory set for a low end of 18hz, but this is easily adjusted up or down by switching plug in resistors (BagEnd can furnish a PDF explaining and diagramming all you need). I'm planning to increase the cut off on mine to about 25hz, as recommended by the ELF Guide. That way, less amp power will go to nonmusical (ie low string-handling sound and rumble) sound, leaving better headroom.
The ELF cabs sound horrible without the processor. Keep in mind, the cab is a 3 cubic foot, sealed box.
I live pretty close to Uncle Bob's (my Eden came from there). I was actually planning to try out two ELF cabs with my rack to see if I'd have any power problems adding a second ELF 18. The last time I was in they had about 15 ELF 18s, including a rig they were selling for some guy with 10 ELF 18s, plus processor for $2,500 (that's $250 a cab, folks - anyone interested in forming a buying consortium?).
Bill