Onto the (very long) comments:
I replaced a fully-modified Behringer DCS2496 (every mod available) with the dspMusik. I've had the DCX in my system for about a year and was pretty happy with it: fully configurable both as a crossover and to enable some room correction. The settings: a 4th order LR at 86 Hz with a PEQ in the subs to fix a narrow band resonance and a PEQ in the mains to fix a broadband mid-bass/lower-mid resonance. Those modes were based on very simple averaged noise measurements I made with an NTI Acoustilizer meter.
Before I put the subs back in the system, I drove my digital sources through a Benchmark DAC-1. A reasonably-priced, awesome sounding device, in my opinion. If I only had a multiple-channel version of one of those to put behind a purely digital in/digital out crossover, that would be it. (Actually, it was at a dinner with Rich when I told him this, he looked up, gave me one of those 'Rich looks' and told me 'already got it, just wait a bit' The wait has been worth it, big time!)
Rich cloned my DCX settings exactly, but cut out all of the unused Behringer processing blocks. I got both units installed and loaded up the dspMusik. Rich talked me through everything. No problems, easy...
Since nearly all my listening comes from SPDIF sources, I started there. No USB or analog connected. 1st time I ran up the volume I noticed a very significant amount of hiss from my music server (not there with the DCX). So, I tried the CD and ProTools and the hiss was either gone or dramatically reduced. I have pretty long SPDIF cables (all Apogee Wyde-Eye) so Rich and I guessed it could be cable length. I bypassed my SPDIF selector switch and that seemed to help.
(My music server runs JRiver MC20 and all my FLAC files are 44.1/16) I just started out with a playlist I use when I make system changes. What I heard in a nutshell: an improved ability to follow reverb tails, great control over dynamics, complex waveforms don't seem to bother this, great headroom. The bass seems better but I thought it was too low overall.
And that's when I made my 1st mistake: I decided to adjust the bass volume in real time using AudioWeaver. I didn't realize the adjustment range on these controls defaulted to +/-100 dB! I tried to type in a 1 dB increase but I didn't get that quite right and increased the volume by some number that probably can't be typed without the use of logarithms. To make matters worse, I was tweaking the Left Main, not the Left Sub. That's when I thought I destroyed one N2X. After I calmed down, I went back and adjusted all volume sliders for a -10 to 0 dB range. whew....
Moral of the story - if you want to tweak things, DON'T DO IT IN REAL TIME WITH LIVE SIGNALS.
I also listened to some of my (amateur) recordings: solo classical piano, straight jazz, fusion, simple acoustic stuff, Motown/R&B. Everything just sounded better as noted above.
So, I'm pretty much happy, no? And then Rich unleashes the Apodizing DAC filters on me... OMG!!!
A new dsp load and the sonics are just more of what I heard to start. Reverb tails/delays - one of the hallmarks of the nCore's - I'm now able to actually detect the onset of a delay and hear the repeats in the recordings. They tails just extended even more - you can follow them well after the next transient comes in. Bass - solidified on the extreme low end. It's the same sense as when you move a low frequency corner down another octave. Impressive! Percussion: the edges are just so well etched in time it's uncanny. Imaging is still there.
Sunday was on to the analog input. I don't sense the A/D getting in the way, at all. Been cycling through a lot of different recordings and I don't sense any significant loss but I haven't yet played the SP-9 output directly into the nCores (I'd lose the bass that way).
An astute reviewer would swap back and forth. Unfortunately (fortunately?) I see no reason to go back. I'm sold - the dspMusik is hands-down the better device. there are user-interface things that need to be addressed, but the sonics so far out-weigh the convenience of the alternative, it's not that big of an issue.
Conclusion - the dspMusik is a major league audio device that still has room to grow. Likely not much sonically, but certainly from an end-user perspective. Given that I have the same amount of $$$ invested in this as I have in the fully-modded DCX, that's a clear win in the value camp.
Sorry for the long-winded post....