SMR LogoNHT 2.5i and SA-2 Review

The NHT 2.5i loudspeakers, part of the Focused Image Geometry Series set a standard which is hard to beat at the price-point, coupled with the NHT SA-2 sub-woofer amplifier, the combination is impressive to say the least. , nailed down all freestanding objects and evaluated the NHT's for SMR Home Theatre.

Many thanks go to Mr. Ken Kantor and Mr. Eric Suh for all their help and for providing the review samples.

NHT 2.5i loudspeakers

Price per pair: $1300
System Type: 3 way vented design
Response 29Hz-25kHz +/- 3dB
Sensitivity 86dB (2.83V at 1M)
Impedance: 6 ohms nominal, 3.6 ohms minimum
Recommended Amp Power: 35W/ch minimum, 200W/ch maximum
Weight: 53lbs. each
Finish: High gloss black, mahogany or sycamore laminate (all specs as per manufacturer)

NHT SA-2 Sub-woofer Power Amplifier

Price: $440
Amplifier Power Rating: 120 watts RMS into 8 ohms, 150 watts into 4 ohms.

THD: Less than 0.03% at full volume

(All specifications as per manufacturer)

You know, the last couple weeks have made me really appreciate my dedicated listening room. The best part of such a room is the fact that you can nail everything in it down so that things don't rattle off the shelves when the bass notes start pluming the depths. I havent used that room for my auditioning of the NHT 2.5i and its been a real awakening as to how lucky Ive been! These speakers have been driving me nuts! When I read the description of the drivers used for the "sub" woofers, I didn't expect much. How much air can a pair of 8 inch drivers move anyway?? Well, let me tell you: Plenty!! The prodigious bass output from the 2.5i has had me chasing down rattles all over the first floor of this house! But the good news is that thats not even close to their best feature. The bad news is that my enthusiasm has me ahead of myself!

NHT 2.5i loudspeakerMy review pair of speakers came in the standard NHT black laminate. If youve seen their pictures in the magazines, you may be surprised how nice they actually look in the home environment, I was. Everybody coming into the house has taken note of them and in a good way too. Standing 38 inches high (off the carpet), 15 inches deep and 7 inches wide, they wont be described as imposing. They have an extremely clean appearance with only two drivers visible from the front (a one inch aluminum dome and a 6 inch polypropylene with inverted dust cup and vulcanized rubber surround midrange/woofer) with the 8 inch woofer (also polypropylene of the same design and origin as the midrange) on the inside edge, a bit toward the rear. At the bottom of the finished rear are two sets of 5 way binding posts connected with gold plated jumpers and a little further up, a bass port.

I also requested the SA-2 bass amp from NHT . This amp was originally designed to power the SW-2 slave subwoofer from NHT. It delivers 120 watts and the two of them together make up the SW-2Pi. The amp has a continuously variable low pass filter on its rear as well as a phase switch, a defeatable "stand by mode" switch (designed to automatically turn unit on when a signal is present and then turn off when no signal is detected for 10 min), an adjustable high pass filter with set frequencies of 50, 75 and 110Hz. The high pass filter is used when using the unit to remove the bass from the signal and passing it on to the main speakers either through the speaker level inputs and outputs or the line level output. Signal input can be achieved either by RCAs via a preamp output or by speaker leads.

The reason I requested the SA-2 was the proliferation of speakers with powered subwoofers in the market today. It was my thought that a speaker which is fundamentally good on music and a good bass amp would be a great alternative to this new wave of speakers. One negative I see in those subwooferd speakers is the fact that you have the speaker, the amp and the subwoofer all tied together. Outgrow any single element, and you must get rid of it all. Its much the same argument against the ability to upgrade receivers. But with the NHT combo, you can buy the speakers now and live very happily. Then, in the future, you can buy the SA-2 and have killer bass for your video system too. Should you ever want to upgrade the speakers, you can sell the speakers, keep the amp, buy another one and upgrade to the flagship 3.3 using them on the new speakers and be that much ahead of the game. Or if you wanted to go the satellite/sub direction, you can do that too. Buy a quality pair of satellites and NHTs own SW-2. Of course, I still had to find out if the speakers were to my liking and if the combination worked well. They were and it did.

Upon arrival, the first thing I did was hook the speakers up to a Rotel integrated amp. I didnt even unpack the bass amp. I wanted to hear the 2.5is by themselves. I ran music through them during the daytime hours for 3 straight days to break them in. I did a bit of listening to them during this period of time and they never sounded bad. They never sounded as if there just must be something to be gained by break in. This was promising. After about 40 plus hours of playback, it was time to give a serious listen. Wow! That bass! With the 60 watt Rotel, these speakers were cranking and the bass was shaking walls! Rock music had a foundation that I've not heard in speakers anywhere near this price range. And tight?? You bet! I was truly impressed. One problem though. Too much of a good thing. I had about 18 inches between the rear of the speaker and the wall and it was pretty clear that they were a touch too close. This is where I learned one of the beautiful things about this speaker. With the woofer where it is, at the bottom rear of the speaker, and with the rear facing port, these speakers can be very nicely tuned to your room by placing them closer or further from the wall. Now, this is a problem on many speakers because as the speaker is moved toward the wall, imaging suffers. This isn't a problem with the 2.5is because their bass output was so strong it required little if any boundary support. It behooves the owner of this speaker to bring it out into the room where imaging benefits as well as the bass balance. If you are a hard rock listener, this speaker images very well at the 18 inch distance, and you will love the bass too. For other types of music, where perhaps a more natural bass is required, the whole sonic picture benefits from fine tuning, ie: changing the distance to the rear wall. I eventually wound up 24 inches out which placed the front of the speaker 39 inches out. Is 39 inches more room than you can afford?? Relax, there is another way!

NHT SA-2 Sub-woofer AmplifierEnter the SA-2. With its front mounted volume control, myriad of adjustments on the rear, and flexible hook up, it offers complete control over the bass. The fact that you now have an additional 120 watts at your dynamic disposal is only the frosting on the cake. Bass adjustment and control is so complete with this amp that you can place the speakers closer to the rear wall and bring everything back into balance. This is the best feature of the SA-2, it offers a fantastic amount of control allowing you to tailor the bass to your every whim. So tailor I did.

With the rear of the speakers now placed 20 inches from the wall, the SA-2 installed and adjusted, it was time to move on to the rest of the spectrum. Ive long been a fan of NHTs midrange. Starting with the little SuperZero, all NHTs midranges are squeaky clean. Is that a poor choice of words? Definitely! But its true. Only under the most harsh and exceptional of circumstances have I ever heard an NHT midrange cloud up and become confused or opaque. The 2.5is were no exception. The midrange was always detailed and neat. The upper midrange was one of my favorite parts of the speakers performance. Its a popular misconception that bright speakers are bright because of an over active tweeter. Not so, it's the upper midrange which determines the level of brilliance. I dont like bright speakers. I always say "speakers sparkle, music doesnt". Nothing reminds me that Im listening to reproduced sound like a bright speaker. Some speakers have that brightness voiced right in because people think it sounds more detailed. Well, give me a tiny bit less perceived detail and a whole lot less glare and Ill be happy. After a long listening session, Ill have less listener fatigue also.

NHT 2.5i LoudspeakerMoving on to the tweeter which is the same aluminum dome used in their flagship 3.3, the best compliment I can give it is to discribe it as being without character or sonic signature. What? You need more than that? OK, I can tell you this, at no time did the tweeter ever call attention to itself. Its not hard, its not soft. Its not edgy, its not etched. Like the midrange, it just doesnt do anything to call attention to itself. If anything, its a little, teeny, tiny bit recessed which makes it forgiving of less then state of the art electronics. A cheap Yamaha integrated amp I had laying around the house imparted some midrange hash, but the treble remained fairly innocuous. When I moved up to Conrad Johnson tubed pre amp and power amp, the treble was excellent. These speakers definitely benefit from better electronics (as Ive found the whole NHT line does) but you dont need the most expensive gear to enjoy the music. The Rotel I mentioned earlier did an excellent job too.

OK, no speaker is perfect, so there must be a short coming or two, right? Well, OK, but just a couple minor ones. The speaker lacks, in ultimate terms, the last word in transparency. You just cant hear through the speaker like you can with electrostatics, ribbons and the better examples of mini monitors. To many, that wont even be a hindrance though. For one thing, you wont find any of those speakers anywhere near the NHTs price point. For another, not everybody wants to listen to their music through a microscope. Most live music listening wont get you any more detail that the 2.5i will. This lack of microscopic acuity makes the speakers lend themselves to enjoying the music rather than inviting one to try to listen for what color socks the bass player is wearing. It allows one to enjoy the performance as a whole rather than dicing it up into small sections for closer inspection.

Getting back to the 2.5is bass, Ill tell you that it is what you want to make of it. As long as "bloated", "one notey" and "mushy" arent on the wish list. No matter how I elevated the bass level (within reason) the bass was always extremely taught, very solid and articulate with tremendous texture. One of the reasons for this is the low crossover point of the woofer on the 2.5i of 100Hz which puts it well below the critical midrange. At no time do male vocals become chesty and congested. One of todays audio catch phrases is "rhythm and pace". To me, it boils down to whether or not a speaker can boogie. These NHTs boogie and boogie hard. I defy you to put on some music, turn it up and keep your toes from tapping. Poor bass will always bog down the tempo of a speaker but there is no putting the brakes on these! Add in the SA-2, and nothing changes except that you get more feeling of limitless dynamics. As I said before, you can buy and enjoy the speakers now, and particularly if you want to use the speakers for video, you can pop for the bass amp later.

Jesse Cook - GravityAs I tried to make specific notes while listening to music, I found myself writing the same things over and over. Rhythmic. Excellent bass. Clean. Neutral. Natural. Smooth. Excellent imaging. Wide sound stage. No matter what I played, the notes read the same. For example, the song "Azul" on Jesse Cooks "Gravity" CD, exhibited excellent sound staging and imaging height. The captivating rhythm on "Brio" was just that. Imaging was excellent as the two rhythm guitars imaged to the outside left and right of the speakers with a very solid lead guitar in the center. While Ive heard more texture from the stings on more expensive speakers, what I heard was very natural and extremely convincing.

On the Eagles "Hell Freezes Over" CD, the bass drum on "Hotel California" was powerful and tight with less overhang than Ive heard on many a speaker. The drum finale on "Get Over It" was as realistic sounding as Ive ever heard it with the right balance of boom to transient attack. The sense of space around it was most impressive also.

On Flim and the BBs "Tricycle", the 2.5is exhibited excellent jump factor on the title cut and again the drums at the end of the cut were fantastic. Drum aficionados will be impressed!

If I havent made my feelings about the NHT 2.5i sufficiently clear, Ill try one more time. These are excellent speakers. I know of no other full range speaker anywhere near their price range that offers the degree of neutrality, midrange clarity, balance and top to bottom coherence that these do. As the bass performance was perhaps the most surprising part of the package, these speakers are a must audition for Rock and Rollers as well as Jazz fans. Listeners of other types of music would be doing themselves a disservice by passing them by too. They are just too good across the board.

Throw in the SA-2 bass amp and you have a leg up in the home theater set up too. It offers a large degree of adjustment in the bass which usually comes in handy for video in particular. For the investment, I cant think of a better speaker/subwoofer combination.

Im really going to miss these speakers when theyre gone. I heartily recommend anybody in the market for a pair of speakers for either music or video (or both) to go out of their way to find a pair of the NHT 2.5is. Just make sure you nail down all those rattles first!!


Good luck and listening,



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