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  3. 153097-12620

GR Research NX-Otica and Servo OB Subs

I am amazed that these speakers (and other models from GR Research) have not garnered more attention on Audiogon. For about $6K, and 40-50 hours of work, I now have a set of speakers that is, by far, the best speakers I've ever owned. And I have owned some fairly good speakers including Tympani IVs with Entec servo subs, Duntech Sovereigns, Revel Ultima Gems with dual Revel Ultima Subs, Revel Studios, among others.

The NX-Otica, along with GR Research's other speaker designs, are DIY designs. I know that scares a lot of people off, but they are really not difficult to build. For the NX-Otica and stereo triple 12" open baffle servo subs that I built, GR Research has teamed up with a woodworking company to produce MDF flatpacks which just need to be glued up to create extremely robust and well constructed cabinets. GR Research provides everything else.

The NX-Otica is an open baffle design with a narrow (~8 inch) front baffle and side wings to reduce dipole cancellation. The driver complement is a planar magnetic NEO 3 tweeter (in a wave guide), two 6 inch midrange drivers with phase plugs in an MTM array. The wave guide allows the tweeter to cross over fairly low, while the midrange phase plugs allow the driver radiation pattern to more closely match the tweeter at the crossover point. Four 6" woofers complete each tower.

The NX-Otica by itself only reaches down to 40-70Hz depending on the room, and are designed to be used with the servo open-baffle subs. I finished the NX-Oticas a couple weeks before the subs, and in my room they didn't really sound that bass shy on most recordings, but the subs really complete the package.

The crossover components supplied by GR Research are stellar quality with a mix of heavy gauge copper coil inductors, copper foil inductors, sonicaps, miflex copper bypass caps. In other words, these crossovers put most crossovers you'd find in sub $20K speakers to shame.

I've never built a DIY speaker before, and I think I jumped into the deep end with these speakers. The large number of drivers and fairly complex crossover make this a somewhat more challenging project than many kit speakers, but they really weren't that hard to build and Danny Ritchie from GR as well as numerous other builders on Audio Circle, are there to help.

There are obvious downsides to this system: You have to spend some time to build them unless you pay someone else to do it for you which ups the cost. Their complex front baffle shape makes them hard to veneer although some builders have veneered the side panels. I decided to just paint the whole speaker. This was by far the most time consuming part. I don't have great painting skills and have never painted anything like this, but they came out fairly nice. I think if you had another couple $K to invest, you could take the built cabinets to a cabinet shop or auto-body shop and have them professional sprayed and could get a much more professional finish.

Open baffle speakers aren't for everyone. They need a fairly large room. I have mine in a 17' x 27' room, with the front of the baffle about 6 1/2' from the front (17') wall. The two cabinet per channel design takes up a lot of space.

And probably the biggest downside is resale. Even if more people knew how good these speakers sound, finish quality is an unknown, so it's unlikely a buyer would be willing to buy them sight unseen.

But the upsides are huge. For a relatively modest investment in time and money, you get a speaker system that sounds amazing. They have the open, airy sound of magnepans with more precise imaging due to the narrow baffle. They have thunderous, fast bass that doesn't energize lateral room modes and transmits a lot less of the bass energy through the walls. They are efficient (93db/w), easy to drive, and very dynamic, with a beautifully smooth and detailed midrange and high end. Vocals - both male and female - sound amazing.

Sorry for the very lengthy post, but it's hard to stop gushing about these speakers. I've only heard a few other speakers that sounded all-around as good to me as these, and they were ~10 times the cost.
128x128jaytor
brewmasterdon
68 posts
 

I had the opportunity to visit Danny a couple weeks back and listen to the new line forces, which were made from a composite material compared to the originals that were made from aluminum (~200lbs), they were outstanding to say the least, it is hard to describe the realism that those speakers portray without actually hearing them, I had their sound in my head for 3 years!! The new version also have a far more expensive x-over network that is truly next level with his new copper capacitors. Danny mentioned that him and I were the only two people to have heard both versions and although the cost of entry is not for everyone, if your able to hear a pair it is something that you will not soon forget!! As for the open baffle subs, I've owned duals, triples and quads, basically the more you have, the fuller the overall bass realism gets and it really depends on the size of the room as to if you overload it or not, the beauty of the system is you can have more or less at the turn of a button.


Jaytor; great write up,

bdp24; the guy in Canada is my partner Jay, quite possibly the most honest guy in audio, and you're right, Danny is a master speaker designer, as well as an all around great guy,


Cheers,


Don

sunshdw's avatar
sunshdw
252 posts
 
Man, I want to try this speaker/sub combo out sooooo bad. I emailed GR and told them about my smallish (11.5W x 14D x 8H) room and Danny's response was " Open baffle speakers like the NX-Otica are more room friendly than a set of mini-monitors." and then followed with " Any open baffle speaker must be pulled at least three feet or more out into the room." The latter answer makes me very nervous since that would put the speaker about 6' apart and about 7' from my chair making them nearly a spendy set of headphones. 

brewmasterdon
68 posts
 

Don't quote me, but I believe that Jay's NX-Otica's played flat down to around 40 with a bit of PEQing in a room that is very similar size wise so it's really about what your willing to live with sub sonically, that said, a pair of OB subs really rounds out the sound.


Don

jaytor's avatar
jaytor OP
765 posts
 
@brewmasterdon - You and Jay do great work! I was really impressed with the quality of the flat packs and how easy they went together. 

I'm watching Danny's development of the Line Force with some interest. My wife would not be happy if I built another speaker system any time soon, particularly at the cost these are likely to run, but maybe in a couple of years... In the meantime, the NX-Oticas are pretty spectacular and I'm sure are far from the weak link in my system.

@sunshdw - I think you could probably get away with placing the speakers a bit closer to the side walls, particularly with a little acoustic treatment, but distance from the front wall is more important. Keep in mind that this is the distance from the front baffle to the wall. 

In my fairly large room (17' x 27' x 8'), the NX-Oticas by themselves were reaching down into the mid 40's Hz range. For a lot of music, this was just fine.  I think in a smaller room, they'd reach even lower.

That said, I'd probably be looking at one of Danny's smaller designs for a room your size. Maybe the new Super Mini design (once Danny has the NEO10 drivers ready) mounted on a sub of some kind. Give Danny a call and discuss what you're looking for. 

- Jay
brewmasterdon
68 posts
 

Thanks;

I think guys would be shocked at how well the Super mini's image, I was!!, not to change direction, but we have already sent Danny the prototype bass section that includes 4-6.5inch drivers but he's simply been to busy to measure them, but that also maybe a good solution with the room capacity, both options have different strengths so it really depends on your end goal.


Don

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