NHT Super Audio 5.1 Theater System 
Home Theater Loudspeakers Speaker Systems
Written by Tim Hart   
Saturday, 01 December 2001

Home theater enthusiasts never had it so good. It used to be that the choices for a good 5.1 speaker package were either far beyond most people’s means, or so inexpensive that you had to wonder how the manufacturer could ever make money selling them. Then there are speaker packages (you know the which ones I am talking about) which have incredible marketing behind spectacularly mediocre products that the unenlightened seem to be enamored of due to the diminutive size of the items. High-end manufacturers over the past few years have heard the cry from folks begging to step up to higher-performance speakers, questioning why products have to cost so much to sound so good. When the companies trickle down their very expensive technologies into more affordable products, they offer an opportunity for the masses to expose themselves to the high-end performance arena. NHT is one of those companies, and their latest effort is the Super Audio series of home theater speakers.

NHT has long been regarded as a high-end loudspeaker manufacturer that prides itself on giving their customers the most performance per dollar spent. With a broad product line that ranges from the critically acclaimed 3.3’s down to the cost effective Super Zero, NHT has products that will satisfy any budget or performance requirement. NHT’s latest product, the Super Audio series, builds on the value of its predecessors by enhancing sonic performance and offering a new look while maintaining the signature NHT sound. A few of the improvements include enhanced driver response, featuring a low-distortion/high-power one-inch dome tweeter and high-excursion polypropylene woofers that are said to provide more accurate sound staging, better low-frequency performance and a smoother overall presentation.

The industrial design of the Super Audio series has taken on a more modern presentation, deviating from the traditional NHT look with rounded edges and the familiar high gloss black lacquer finish that will certainly catch the eye, giving the owner a product with the appearance of a system that provokes envy from visiting family members and friends.

The 5.1 speaker package I received from NHT includes ST4s as the front speakers, SB3s as the rear speakers, the SC1 as the center channel, and the SubOne I to plumb the lower octaves.

The ST4 is a floor-standing loudspeaker system ($999.95 a pair) which stands 38 inches tall, eight inches wide and 12 inches deep, weighing in at 47.5 pounds. A relative of the SuperTwo, the ST4 is a two-way hybrid design that has two separate chambers. The top sealed chamber has a one-inch fluid-cooled tweeter with a neodymium magnet mounted below a 6.5-inch midrange driver. In the lower ported chamber resides an eight-inch-long throw side-firing polypropylene subwoofer. This is said to give the ST4 the midrange clarity and detail of the finest two-way designs, combined with the dynamic range of a three-way system. The frequency response of the ST4 is 31Hz-22kHz +/- 3dB, with a sensitivity of 86dB, a moderately hard load to drive, and a power handling capability of 200 watts. The top enclosure is video-shielded for use in close proximity to TVs.

On the back of the enclosure, you will find two sets of speaker binding posts with jumpers. You can easily hook up a variety of different connectors, such as spade lugs or banana jacks, as well as running bi-wire or bi-amp mode. Due to the side-firing bass woofer, careful placement of the ST4 is necessary to avoid anomalies created by objects near the woofers, and a fully adjustable spike kit is provided to facilitate that placement.

The SB3s ($299.99) that I used as the surround speakers are identical to the ST4s, less the subwoofer. With a two-way design, the SB3 utilizes the same tweeter and 6.5-inch midrange driver in a smaller enclosure. Measuring 13 inches tall, eight inches wide and 10 inches deep and weighing in at 16 pounds, the SB3 can be easily placed for optimum performance just about anywhere. The SB3 has a fairly wide frequency response of 39Hz-22kHz +/- 3dB, a sensitivity of 86dB, and a generous power handling capability of 175 watts. Although not bi-wireable, the SB3 features the same easy-to-access binding posts as the ST4, as well as video shielding for minimum placement restrictions. I chose to stand-mount the SB3s on 24 inch-stands that put the speakers approximately at the same height as the drivers on the ST4s.

To handle the majority of the workload for movies, the two-way SC1 center channel utilizes two horizontally-mounted 4.5-inch-long throw woofers, with the same one-inch fluid-cooled tweeter as the ST4 and the SBS mounted in the center. My first thought when I saw the SC1 was, "Is it big enough?" I’ll reserve judgment until later, but I must admit that I was a little skeptical as to whether or not it would be up to the challenge. Video shielding is a given for this enclosure, whichh is 6.63-inch high, 14.5-inch wide and 5.63-inch deep. The frequency response of the SC1 is 78Hz – 22kHz, +/- 3dB, with a measured sensitivity of 86dB.

When positioning the speakers, I first checked the manuals supplied with the loudspeakers to see what NHT recommended, and used that as a starting point. NHT suggests that the listening distance from the front of the main loudspeakers to the listener should be one-and-a -half times the distance from center to center between the main loudspeakers. It is also suggested that the rear channels be equidistant to the front loudspeakers for optimum sound. Although these loudspeakers are diminutive in size and will not dominate your living space, my situation doesn’t allow for that type of placement, and I suspect that 80 percent of the home theater owners have similar circumstances. The ST4s ended up one-and-one-half feet from the front wall and four feet from the side walls. The SB3s were placed behind and to the sides of my couch, which left them sitting about a foot wider apart than the ST4s. The SC1 I placed on top of the TV and the SubOne I went to the right corner, which meant it was behind and three feet to the side of the ST4. During set-up, I programmed the distances on my B&K 307 receiver to compensate for the placement discrepancy of the SB3s. After setting up the correct dB gain on each channel relative to my room response, and positioning the ST4s and the SC1 on an arc to insure their respective distances from the listening position, I focused on getting the subwoofer situated.

The SubOne I ($799.99) is an upgraded version of the SubOne, utilizing a larger 12-inch-long throw polypropylene driver, a built-in 250 watt amplifier and an outboard controller, which is a licensed technology from the Sunfire corporation. This 16-inch cube, which has a separate, two-inch high, 11-inch wide, seven-inch deep controller, weighs in at a solid 50 pounds, with a frequency response of 25 Hz – 180Hz +/- 3dB and a distortion of less than 0.3 percent at full power. The low pass crossover is continuously variable between 40-180Hz at 18dB/octave. On the high-pass side, you can choose from a selectable 50, 75 or 110Hz, 12dB/octave for line level input, or a fixed 100Hz at eight ohms. The controller allows the user the capability to run four different loudspeaker configurations. You can run your main loudspeakers through the SubOne I controller, taking advantage of its selectable 50-110Hz high-pass line-level filter or the fixed 100Hz (8 ohms), sending only those frequencies above that threshold to your main channels. Alternatively, you can run the SB4’s full range as I did, using the continuously variable low-pass filter that adjusts between 40-180Hz at 18dB/octave, based on the performance range of your main loudspeakers. I prefer this method as it eliminates a whole level of loudspeaker circuitry that to me has the potential to do more harm than good. Because the B&K provides a LFE channel, I ran the ST4’s full range, bypassing the internal low-pass filter so that I didn’t have two filters in series.

Phase and gain can be adjusted by the twist of a knob. There is also a flat/video contour switch, which allows you to optimize the SubOne I’s performance for music or movies, giving the SubOne I a boosted output between 40Hz and the low-pass frequency, and rolling off the response below 35Hz, which provides greater power handling at higher volumes. This emphasizes sounds like explosions and gunfire. For music, some listeners like myself prefer a flatter bass response. With the flip of the switch, you can tailor the bass response for more critical listening.

Having the SubOne I controller on top of the sub makes adjustments a snap. You don’t have to stand on your head to get this puppy dialed in, which is a welcome advantage, as opposed to performing contortionist acts to get access to the rear panel-mounted controls on most other subwoofer products.

Movies and Music
After I was satisfied that all adjustments, settings and speaker placements were to my liking, I gave the NHTs roughly 50 hours of break-in time with a variety of material. After that was done, I jotted down my first impressions. With the ST4s, SB3s, and the SC1, what I heard initially was a top-end that appeared a bit hard and bright, but as I got to know these products more intimately, transparent better describes the upper octaves. There was little noticeable coloration with the different material I was playing.

As the NHT products became more familiar to me, I refined my impression of their sound to fast, taut and lean, with the lower octaves tight and punchy. What at first seemed somewhat etched and bright became more a sparkling quality. The ST4s and the SB3s top end was crisply presented with very little coloration, and the SC1 meshed fairly well with them, considering the smaller drivers that their bigger brothers boast.

To put the NHTs to the test, I put in my new reference DVD, "Star Wars: Episode I -- The Phantom Menace (20th Century Fox Home Entertainment). This DVD really challenges the loudspeaker design in how seamlessly the sound moves from one channel to the next. This 5.1 mix is the best I’ve heard in accurately following the onscreen cues to near perfection and the mixing is superb. Testing the timbre and tonal matching of any 5.1 speaker system, the famed pod race puts all channels through their paces, demonstrating not only the loudspeakers' ability to handle the transient and dynamic portion of the soundtrack, and how well the sub and satellites blend, but also how well they portray the spatial cues that are abundant in this DVD. The NHTs do a nice job of sorting out most of the information in a enveloping way, at times putting me out in the desert as the pod racers speed by.

The SubOne I seems just right for the satellites, never too overbearing or plodding. The space battle has Naboo fighters swarming my living room like tiny bees and the location of their sound is very convincing, with explosions and laser blasts shaking my room with authority.

In the beginning of The Mummy Returns (Universal Studios Home Video), the battle led by the Scorpion King portrays two mighty armies facing each other. At their leaders' command, the warriors rush into each other headlong. The visceral clash of their impact against one another made me blink. The sound of swords drawn from their scabbards and the harsh clash as the weapons met at times had me convinced they were right in front of me. In another scene, where Rick and Evie rob the Scorpion King's tomb, the sounds of spirits and the echo of the torch and footsteps in the cavern leading to the tomb are deep and spacious, capturing the ambience of a scary, dank environment.

I still felt that the NHT’s weren’t giving me all they had, so to get a more familiar midrange reference, I popped in Steve Stevens’ Flamenco A Go Go (DTS Entertainment). Bass and midrange bloom are the hallmark of this live 5.1 recording, as well as loads of detail. The NHTs do a credible job of delineating the transients on "Our Man in Istanbul," but not quite fleshing out the midrange as I've heard it on other loudspeakers, like the slightly more expensive Monitor Audio GR10s. On the other hand, the bass control is very nicely presented, giving me a nice tight and quick punch where it should on this track, and providing top-end detail that is enjoyable and engaging.

This is readily apparent on the DVD of Alice In Chains MTV Unplugged (Sony). The transients of the strings on the frets of the acoustic guitars are engagingly detailed, although slightly veiled in comparison to my Monitor Audio Gold Reference Series loudspeakers. But that is not really a fair comparison, as the Monitor Audios are three times the price of the Super Audio series by NHT. The air and dynamics of "Angry Chair" are handled well at louder volumes, conveying good tonal balance for a loudspeaker of this price range, with enough bloom for decent warmth, but leaving me wanting a bit more. I think it more acceptable to err on the side of a flatter response, which it sounds like NHT has chosen to do. I approve.

What I found out when I put the ST4s in my reference two-channel system was that these speakers play bigger than their price tag. Imaging, while not pinpoint, is very good, with nice layering and depth. When playing loud, such as with "Fighting With Clay" from Days of the New’s latest Red CD (Geffen), the ST4s rock hard, only sounding slightly compressed on the higher octaves, but never straining to the point of harshness. The bass really comes impressively alive. The upper midrange and tweeter blend well with the bass driver, never seeming out of step with one another.

The Downside
I feel that the 86dB efficiency was responsible for some, if not all, of the midrange reticence that I was experiencing. When the efficiency of a speaker is challenging, it requires a bit more authority in the amplifier to overcome this characteristic. When under-driven, the speakers don’t appear to come alive until you really push them. This affects the speakers' ability to produce their full range and has other undesirable effects, such as a compressed or strained demeanor. Although I point this out, it is not a huge issue. I am being picky here. Most people would not have an problem with this effect, or even notice it. It is important to note that the quality and quantity of amplification will determine how well the NHTs will perform for you. Careful matching is a must at this level, and you do not want to find out later that to get the performance you heard at the dealer, you may have to plunk down some additional cash to get you where you thought you were going to be when you arrived home with your new system.

For the money, I think the playing field is significantly narrowed by these NHT products. They are not the cheapest products out there, but they aren’t anywhere near the big dollar category, either. They make it very possible to obtain very good performance at a price point that won’t demand half a year's worth of your salary. I had a lot of fun with these speakers, which is exactly what you want your speaker investment to give you. Take a test drive and I’m sure you’ll agree that NHT’s philosophy of more for your money comes through loud and clear.
Manufacturer NHT
Model Super Audio 5.1 Theater System
Reviewer Tim Hart

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