I have had these a few months now.
First up the usual packaging. The box is nicer then the usual car audio box we see. It opens up like a treasure chest and the packaging is simple with just a bit of foam to keep the amp secure.
When looking at the amp, I find it to be a particularly handsome design. Simple black anodized heat sync. I love these small foot print rectangular shape amps. A lot of people like the square shape that fits under a seat, but I find if you want to hide an amp anywhere else, the rectangle is the way to go.
So lets look at the specs.
120 x 4 rms @ 4ohms(ClassAB) and 800rms x 1@ 1 ohm(classD).
That's a lot of power for such a small package. I included the audio precision PDF files for the NX4 and the N2 (the NX5 is basically those 2 amps in the same chassis). As you can see it's pretty much right on. Of course the 2ohm rating for the multi channel part is more of a "peak" rating and is not realistic at all, however I don't particularly care about that since I use them at 4ohms.
Lets look at the guts, we all love that.
I was a bit worried about how these would end up working day to day, being class AB and such a small chassis.These amp I am told have protection if they overheat. I have not witnessed overheating though so I can't talk about that part. I didn't have them during the hottest part of the summer. They do get hot to the touch after a bit of playing time. I can easily tell what side is the AB side and what side is the class D hehe.
So what are my impressions? They are SMALL the biggest is the 5 channel at only 15" x 5.5" x 2.1". Ever since small foot print amps have been made available I go crazy for them. I have used -in the small amp category- sony xm-4s and xm1s as well as the planet audio BB75.4 and 175.4 and I prefer these by far. The nx4 and nx2 are ridiculously small, one could easily fit one per door bridge for dedicated midbases. The noise floor is lower then the sony and the PA amps, and I didn't find those bad in the noise department. I have not had any engine whine either. This makes me a happy camper.
Power wise,subjectively I feel I am getting more power then with the sony's (rated at 50 x 4) and similar to the BB amps(140 x 4). OF course the PDF's show exactly what one gets when buying these amps. Rarely will a company provide this type of info on their products.
I also got the stacking hardware for these and the base knob. The RBK is a boost centered at 50hz that I have not used yet and I haven't tried the stacking yet either. These went right in the car and were put to good use.
The xovers and gain knobs have detents or clicks which I really like. Unfortunately massive has not "normalized" or averaged the clicks to set points. So when setting them one has to go by ear as it really is a guess. One thing I don't like is the front channels on the nx5 and nx4 can only by all pass or high pass, no low pass and the rears can't be band passed.... but that's nitpicking as most amps don't offer this especially in this regardless of foot print. Also the RBK and stacking kits have to be bought separately.
I started originally with these bridged to the massive ck6 stage 3 set and boy it got loud and those mids shook the car without problems. These tiny amps deliver the goods.
Usually I am always looking at changing amplifiers, trying to find better or smaller. But really, it doesn't get any smaller and they are powerful enough to satisfy my requirements fully (And then some). I bought a pair of the NX5's and they take up almost no room and I get a total of 10 freaking channels in a 15" x 5.5" x 4ish" foot print that can be stacked vertically or horizontally.
I really didn't think I would be able to get such a nice small foot print 5 channel with a powerful sub channel, but these fit the bill nicely.
Big thumbs up on my end.
Also a note about the customer service at Massive audio. Their forum is full of positive experiences , but I have to say that it is the best service I have ever received bar none. Not to mention they have some of their techs on their sites forum to give advice and opinions.
-Handsome, simple design (These are really nice in person)
-Tiny foot print
-bridgeable (some small foot print amps aren't)
-1ohm stable (sub channel) I know many prefer not to run at 1ohm, I personally run them at 2ohm and feel I get enough power, but I like the flexibility aspect.
-optional base knob
-All the latest protection circuitry one would expect
-The speaker terminals can handle big speaker wire and the metal "clamp" and screw can't be completely unscrewed making it easy to stuff huge wires in there.
-All power and speaker terminals require the same Philips head to tighten and un-tighten.
-amps don't come with RBK
***Some of you might be looking for the supposed audio precision power output pdf's I am refering to. Unfortunetly CA doesn't allow big enough PDF files so if you want to see them, mosy on over to DIYMA.