Holy Crap What have I done?

Ya know that scene in "Aladdin" where Abu the monkey touches the huge ruby of the forbidden treasure and everything goes to hell around them? Well, *that's* kinda what happened to me tonight.

I finally found a Marchand XM9 crossover at the right price from an honest seller, and it arrived tonight. I put it in line between my preamp and amp, and it did both what I wanted it to do and what I didn't want it to do: it improved the "slam" of the bottom end, but sucked all the air out of the music and my system went from a pretty high degree of "you are there" factor to realizing you're listening to music on a good stereo.

Admittedly, I haven't played with the crossover controls yet, but I'll be quite surprised if they can "bring the life back" to my system.

Any thoughts on how to get my system to give me that "I'm in the room with the musicians" feeling again with the crossover still in line? Maybe I need to go to an XM44, or some other brand of crossover?

I should mention I tried the crossover because my nOrh mini 9.0's only go down to about 65Hz -3dB with a really quick downturn to -10dB (around 55Hz at -10dB, if I remember my measurements correctly.) I was happy with my ACI Titan crossoved over at 85Hz, but had read that using a crossover to cut the lowest octave from the monitors would improve the midrange and imaging. In this case, it didn't, interstingly.

I'd sure appreciate whatever thoughts you all have on where to go next.

TO FAST. Work with the crossover. I added a subwoofer for lower end and the additional reinforcement of the lower tones smoothed out the upper mid band of my system without equalization, "a trick of the ear". Have you tried treating your room for better acoustics? Patience is everything in this hobby however so go slow and listen to the changes.
What is the crossover frequency? I think the Marchand XM9 uses a plug in module.

Marchand X/O are fine sounding units, so you must have some setup thing wrong.
I just read about the XM9 from the mfr's web site. The crossover frequency of XM9L Electronic Crossover Network can easily be set by replacing the set of 2 frequency modules, located inside the cabinet. They can supply any frequency from 10Hz to 20,000Hz. If not specified they will shipped the XM9 with a crossover frequency of 100Hz.
First check what is your crossover frequency. Then we go from there.
Thanks, guys. This unit has the standard 100Hz crossover frequency. Originally I thought this was the best place for it, given the slope diagrams on Marchand's website. It occurs to me, though, that asking my down-firing sub to reproduce frequenies over 100Hz - against the maker (ACI) recommendations - is foolish. I plan to order an 85Hz module today and see how that goes.

Right now I have the sub's crossover set 10Hz higher than the crossover, but I'm not sure that's where it should be. Is there a standard relationship I should be looking for between the electronic crossover frequency and the sub's crossover frequency? Big, I don't think my ACI Titan will allow me to truly bypass its LP filter altogether, but I'll check. That would certainly be best.

Stephenson, I'm delaying room treatments because I'm moving in 3-4 months. I'll certainly look at treatments in the new place, though.

Eldartford, I always enjoy your posts. Thanks for helping me out. I look forward to whatever other thoughts you guys have on this!!

Some different thoughts here: you said when you added the crossover to the system, it sucked all the air out of the music. Are you talking about the portrayal of space, harmonic richness, textures, etc.? If so, the crossover betwen your preamp and amp could ultimately do far more harm than good.

Time and time again, I have found the most critical cable in the system to be the preamp-to-amp link. I have achieved incredible musical magic with the sonic attributes described above. But I can so easily destroy all of this with a change in the IC in this link. And with a crossover here, you have two such ICs in the critical mids/highs.....not to mention all these extra active circuit stages driven by a rather wimpy power supply to boot.

Changing from 100hz to 85hz is just not gonna do anything if you have problems in the upper frequencies. Try the crossover out of the main link and have it drive only the subwoofer as a low-pass and let the main speakers run full range. You lose the benefit of taking the bottom octaves out of the main amp and thus bringing on more clarity in the mids/highs.....but you get the crossover and extra IC out of the loop and this alone can be a huge benefit.

I have found crossovers and equalizers to be fine up to a certain level of system refinement. And yes, they can be beneficial to compensate for low-frequency room nodes, but they can so quickly wipe out the dimensionality and dynamic contrasts that you may have worked so hard to achieve up to that point.