GR Research NX-Extreme

The NX-Oticas are a pretty amazing value if you're willing to put in a little time to put them together. They produce a deep spacious sound stage with excellent clarity and detail and fantastic dynamics. They are very easy to drive with over 93db/watt efficiency. 

Downsides - they need to be several feet into the room to sound their best (mine are set up with the front of the battle about 6.5 ft from the front wall); they really need subs to be truly full range (they go down to 45 or 50 hz on their own, but matched with stereo OB servo subs, they are incredible); and, you have to put them together and finish them yourself (or pay someone to do it)

I really enjoyed the process of building them and am thrilled with the sound. I think these are the most satisfying speakers I've ever owned after 45 years in this hobby (and over a dozen speaker systems, many costing several times the cost of the NX-Oticas with subs).

If you've got high enough ceilings, I expect the NX-Extremes would be a nice step up, From what I've heard, they have a bit more punch in the mid bass and a little more height to the imaging. My ceiling is just under 8' which I don't think is high enough to allow these speakers to sound their best. 

I built the OB subs with three 12" drivers for each channel. Danny's design can be built with 1, 2, 3, 4, or 6 drivers per sub, and flat packed are available for all configurations. The more drivers you have, the less each driver has to work and the faster they will settle when the signal goes away. 

The servo control makes them settle very quickly anyway, but with three drivers (6 for both channels), the bass is extremely fast and articulate. If you've ever heard Magneplanars, particularly larger ones, the bass has a similar quality except the GR subs go considerably deeper and are a bit more dynamic. 

The bass doesn't pressurize the room quite like a sealed box sub, since you are moving air from one part of the room to the other. So musical instruments sound more natural, but movie sound effects such as explosions don't have as much of a shock wave feel. If your primary use is home theater and you like movies with exploding helicopters, I'd probably stick with more conventional sealed box powered subs, but for music, the OB servo subs can't be beat. 

I would expect the OB subs to integrate much easier with the OB speakers compared to a traditional sealed box sub. It's kind of the same issue with trying to integrate subs with Maggie's. But I haven't tried so I don't know for sure. I would post your question on AudioCircle in the GR Research forum to see if anyone else has experience. 

I live in Portland, OR so quite a trek from Michigan. 

It took me about 50 hours to build both the NX-Oticas and subs.  Probably 30 for just the NX-Oticas. Most of that was painting. Building the cabinets was very easy - probably a couple hours total. The crossovers and wiring up the drivers took about 8 hours. And cutting and installing the NoRez for speakers and subs took another few hours. 

I guess it depends on what you are looking for. I find the bass to sound very natural sounding and extremely dynamic, as if you were listening to acoustic instruments in the room. You can still feel the bass, but it's probably a bit closer to what you'd get from a high quality open back headphone (e.g. more sound than pressure).

Hope that helps. 

It does take a decent size room I think, but I found it took less effort to get them (the NX-Otica with triple-stack OB servo subs in my case) to sound quite good compared to conventional box speakers I've owned.

I have a fairly big room (17' x 29') that is reasonably symmetrical, so I have plenty of space to get them out into the room. I set them up about 7' from the back wall and 4' from the side walls and they sounded great. I tried moving them around a bit, but other than some toe-in tweaks, they are pretty much right where I set them up initially. 

I have used Room EQ Wizard to set up the sub amps, which makes it MUCH easier to get them dialed in. But again, I haven't found the need to move the subs around to get good sound. The servo amps provide lots of flexibility in controlling level and phase and also include a single frequency parametric equalizer which I used for one channel to smooth out the bass a bit. The other channel didn't need it. 

I do have a well treated room which helps, but I initially set them up before I had any treatments and they still sounded awfully good. The treatments sharpened the image and smoothed out the bass response a bit, but I think I would have been happy with the sound without most of the treatments. The tube traps in the corners behind the speakers were the first thing I added and made the biggest difference.