Room correction - what device works best?

I just want to thank everyone for making this thread intelligent, informative, encouraging and respectful. I had begun to fade my time on A'gon after too many uninformed opinions delivered with vitriol on too many threads. I am learning something here where the passion for excellent sound is trumping egos.

Bifwynne, did you ever take your preamp out while you used the DEQX?

Unsound ... in a way ... yes. I used my ARC CD-8 CDP as a transport and ran its digital output directly into the DEQX's digital input. On the margin, maybe a little better going "digital" direct as compared to using the CD-8's analogue output into the Ref 5 SE.

Nevertheless, I still use my ARC Ref 5 SE because it is a convenient way to handle other input sources, e.g., phono and TV. IMO, I think the close CDP performance says a lot about ARC gear quality.

Also ... though not logical, I can't bear the thought that my Ref 5 SE may be obsolete. :(

Gentlepeople-
I find this thread to be fascinating because I am not technically inclined but I believe that implementation of digital room and speaker correction may be in my future for several reasons:
1. I'm not a purist.
2. I mostly listen to digital files served wirelessly from a MusicVault server to a Modwright/Logitech Transporter.
3. My Transporter is beginning to fade away, I fear. One of the displays has quit. The work around is to use one of the smartphone/tablet apps, but it reminds me that this is an orphan product with limited; probably very limited repair potential.
4. The dac in the Transporter is limited to 24/96 and while I currently have a relatively low % of hi-rez files I'd like to think that will increase over time.
5. The wireless connection is a weak point because the router and server are upstairs in the SW corner, while the Transporter is downstairs in the NE corner. I know that there are solutions, but still, moving the server so it can be hard-wired to the player/DAC seems like the most foolproof approach.
6. The DEQX or similar device with a DAC could be inserted between the server and my pre-amp w/o having to add an additional A/D step.
7. I am running open baffle speakers w a single driver plus whizzer cone and dual on-baffle subs with the single drivers and subs driven off separate amps. The subs are driven by plate amps which take a speaker level signal from the tube amps that drive the mains. It seems to me that there are ample opportunities for phase and time alignment problems with such a configuration, yet overall, this is the most satisfying system I have had. My system is listed for a more complete description.
8. My system is in my living room, which constrains main speaker placement and rules out any significant room treatments.
9. I don't live too far from Almarg, who has kindly offered to be let me hear for myself what the DEQX product can do, once he gets it dialed in.
10. My speakers do not weigh 300 lbs and I have a large screen porch next to the LR, which I can use for the initial speaker correction analysis.

I'd love to hear thoughts from any of you as to whether or not the DSP approach makes sense under these circumstances. I know there is no substitute for hearing it, but I'm still early in the thinking stage. I'm also curious if anyone has any thoughts about frequency response correction vs. the observations of those who say that a perfectly flat FR sounds "un-natural".

Going to disagree with the 2 sub suggestion, I had 2 sub at one point, it lead to a worse sound than 1 sub.

Putting speaker right at the corners though, now that is magic.