NHT Classic Four Floorstanding Speaker System Review
System Type: 4-way vented floor standing speaker
Frequency Response: 27 Hz–20 kHz [no +/- dB tolerance given on web page specs or in brochure, see attached pictures]
Recommended Power Amplifier Range: 100–250 watts
Sensitivity: (2.83V @ 1m) 86 dB
Nominal Impedance: 6 ohms
Crossover Frequencies: 125 Hz, 800 Hz, 4,000 Hz. NHT specifies the Classic Four with a 12dB LP (low-pass filter) on the subwoofer, 12dB LP/HP (high-pass filter) on the mid-woofer, 12dB/18dB LP/HP on the upper mid-range and 18dB HP on the tweeter.
Side-firing subwoofer: 10-inch black-anodized aluminum cone in rear-vented enclosure
Mid-woofer: 6.5-inch black-anodized aluminum cone in sealed internal enclosure
Midrange: 2-inch anodized aluminum dome
High-Frequency: ¾-inch anodized aluminum dome
Dimensions incl. base (H x W x D): 41” x 7.5” x 16” (13.5” wide to outside of base)
Weight: 65 lbs. ea.
Finish of review samples: Gloss Black
- Smooth, nearly full-range sound from a mid-sized floor-stander
- Extremely wide mid- and high-frequency dispersion
- Can play very loud without audibly objectionable distortion
- Unexpectedly beautiful gloss black finish at this price
- 10-inch “subwoofer” doesn’t obviate need for external subwoofer
- Would like to see premium real wood finish option
NHT is a small but highly respected loudspeaker company located in Benicia, CA. Originally founded in 1987 by speaker industry engineering superstar Ken Kantor (who did the groundbreaking AR Magic Speaker in 1985), NHT has earned a well-deserved reputation for speakers that sound superb, feature innovative, straightforward engineering, and utilize the highest quality materials for great cosmetics and fit-‘n-finish. NHT operates on a direct-from-the-factory business model, which, according to them, saves the intermediary costs of sales reps, distributors and retail markup, allowing NHT to offer a better value directly to the end user.
Designed in California and manufactured in China, the Classic Four is a mid-sized floor stander in their Classic family, which also includes the Classic Three 3-way bookshelf speaker and the Classic Two C and Three C center channel 3-way speakers. All these models use the same 2-inch anodized aluminum dome midrange and ¾-inch anodized aluminum dome tweeter array. At $1,349 each, the Classic Four certainly can’t be considered inexpensive, but just based on the quality of the materials and workmanship, they appear to more than justify their asking price. The head engineer on the Classic Four project was Jay Doherty and the engineer most responsible for the dome mid-tweeter assembly was Jack Hidley. The care and attention to detail in this design was most impressive, as you’ll see as you read the review. But these two gentlemen deserve a conspicuous mention right up front.
At around 41” tall and only 7.5” wide with gently smoothed-off edges, these speakers do not attract a lot of visual attention in the room. They’re attractive but self-effacing and I doubt their visual presence would trigger a dreaded negative WAF to any significant degree.
The Classic Fours were double-boxed in two medium-duty corrugated cartons and had high-quality EPS foam caps and an EPS “waistband” holding the speaker around their midsection, top and bottom. There was a specific Left and Right speaker, even though they differ only in the direction the woofer faces and the woofer is non-directional at and below its crossover frequency. Mostly to make the customer feel good, I suppose. That’s ok. And while bass in this frequency region is omni-directional, some placement situations force a consumer to put one side of the speakers next to a wall unit or in a corner. Also, small changes in room position can have large effects on the bass output. Changing the speaker position so that the woofers face in instead of out might make a difference in output depending on the room shape and listening position.
The packaging was fully up to the task of protecting the speakers, as they arrived in perfect condition after a cross-country (CA to MA) Fed Ex Ground journey. One minor suggestion: I’d recommend that NHT cut small oval hand-holds (about 4 x 1.5”) into the carton, so one person can carry them more easily. As long as it’s not too unwieldy, most adult men can handle a carton between 50-80 lbs without too much difficulty. But you have to have something to grab onto.
Chinese packing material is interesting: Regardless of the so-called “burst rating” printed on the corrugated carton or what kind of internal foam packing material they claim it is, in order to get the “good stuff,” a manufacturer has to pay a Chinese vendor top dollar. Generally, Chinese cartons rated below 200 lbs. burst are made out of what manufacturers derisively call “cheese paper,” flimsy, lightweight material that seems ready to disintegrate under the slightest stress. These cartons had no visible burst test rating certification but were clearly made from very good quality material.
Classic Four in Double-Boxed Packing
Likewise, the internal foam packaging falls into two broad categories: 1) the cheap kind (polystyrene), that breaks into pieces and crumbles into tiny foam sawdust balls that float annoyingly all around the room, rendering impossible any thought of repacking with the foam inserts, and 2) the good foam (polyethylene), which stays together and makes repacking easy and repeatable.
NHT uses very high quality packaging. Having been involved in the design, sourcing and manufacturing of consumer electronics products for decades, I know the cost difference between good and bad materials, and what that says about what a given manufacturer thinks of their products and the image and impression they wish to convey to their customers.
This was a good first step.
The midrange/tweeter grilles were shipped already attached to the speakers but the speakers themselves did not have any kind of protective clear plastic shield placed over the baffle board to protect these delicate upper range drivers during shipping and removal from the carton/initial setup. I have seen many a tweeter dome ruined by wandering fingers as the speaker was grabbed and carelessly pulled out of its box and NHT didn’t take any special efforts to avoid this. No demerits to them for this—this is normal packaging procedure—but they would’ve receive a special shout-out if they had done it.
The speaker’s 2-part (left side/right side) base and the carpet spikes/rubber feet for hardwood floors were packaged in a separate internal cardboard box. The base, made of bulk molding compound or BMC – (also used on truck and airplane parts, and other parts where rugged durability is required) runs almost the full depth of the speaker (about 13 inches) was finished on its upper side to match the gloss black of the cabinet. It was nicely done, solid and beefy. It attached to the underside of the cabinet with three machine screws and an Allen wrench provided in the accessory bag. The threaded inserts themselves were mercifully free of paint contamination or other obstructions and everything snugged down nice and tight, just the way it was supposed to.
Classic Four Accessories and Feet
There was another accessory that was unexpected: A small “double-smile” self-adhesive foam strip (NHT calls it the “moustache”) that went between the dome midrange and the dome tweeter, ostensibly to reduce the effect of any audibly destructive baffle reflections or driver interference that might reduce overall system clarity. While I have no doubt as to the theoretical and measured legitimacy of this device, in terms of its audibility under practical real-world conditions, I’d be willing to wager Gene’s life savings that there would be absolutely zero statistically-significant correlation between its presence or absence during listening sessions of actual program material. But NHT has such a good engineering reputation and I understood exactly why they provided the strips, so I used them. Maybe that was the point after all. The placebo effect among audiophiles can be very strong.
The Classic Four is a true 4-way design. The side-firing woofer handles only the very low, non-directional bass (below 125 Hz) and then hands off, so to speak, to a forward-firing 3-way speaker. Assuming high-quality drive units and good crossover design with steep filters, a good 4-way can achieve excellent deep bass, clear upper bass/lower mids, and then have very small, wide-dispersion units handling the upper frequency ranges. If the designer’s goal is strong deep bass that doesn’t have to handle the vocal range, and then have small, quick, wide-dispersion drivers for the upper middle/treble range, a well-designed 4-way is about the only way to go. Most designers these days do not put much of a premium on ultra-wide midrange and treble dispersion, so for them, larger cone midranges and 1-inch tweeters are just fine. That’s probably the main reason we don’t see small dome midranges used very often these days. A generation ago, dome midranges were commonplace. Nowadays, they’ve fallen out of favor. NHT’s Classic Series is one of the very few modern speaker designs that use a dome midrange.
Remember, dispersion is primarily a function of driver size relative to wavelength. If the driver’s diameter is smaller than the wavelength of the frequency it’s reproducing, the dispersion is very wide. If the driver is larger than the wavelength being reproduced, the driver will “beam” its output forward like a flashlight.
Wide dispersion was a stated design goal for the Classic Four and they went about it the correct way. Each of its four drivers exhibits extremely wide dispersion in their respective assigned frequency range, so the sound is expansive, wide open, very “large.” The downside of super-wide dispersion is a commensurate reduction in so-called pinpoint “imaging,” so the listener has to make the decision as to which design approach they like the best. To overgeneralize, wide-dispersion designs are better suited to two-channel music listening and more focused dispersion may be a bit more suited to multi-channel theater applications, where extremely precise localization and coordination of visual and audible signals are desired. In my room, listening to them strictly in a two-channel music configuration, they sounded truly superb.
The Classic Four might be compact at 41” tall x 7.5” wide, but it’s very heavy for its size and conveys a very solid impression to the user. There are two sets of binding posts, connected by a brass “jumper” strap, just above the rectangular rear vent. The ends of the posts do not have the usually-required plastic CE (European) safety plugs, as I’m used to seeing. Apparently, NHT does not do business in CE countries, so there is no need for those annoying plastic caps. If you want to use banana plugs instead of bare wire to connect the speaker wire to the posts, you’re free to do so. The posts themselves have a nice-sized hole to accept bare wire and that’s how I connected them with 14-ga wire. Nice, easy, and secure. I did not use the bi-amp feature, but it’s nice to know the option exists.
Classic Four Binding Posts
The cabinet itself was made of high-quality MDF, more than 1-inch thick on the front panel. (Again, not all Chinese MDF is created equal—there is “good,” solid Chinese MDF and there is flaky, cheap Chinese MDF. This was the “good” kind. Note: NHT says their MDF and corrugated carton material is imported from New Zealand, not China. The driver areas on the baffle were routed out, so those sections are a little thinner than the rest of the cabinet walls, unfortunately. And interestingly (and surprisingly), the cabinet’s sidewall—where the 10-inch woofer is mounted—is just the standard ¾-inch thickness. I’d have thought that the woofer panel, not the midrange/tweeter panel, would be the thickest since it is most subject to vibration from low frequencies.
Manufacturer’s Comment: The woofer is inset into its own 21mm MDF piece, so the total thickness around the edges is 37mm. In addition, there is a 1mm aluminum sheet glued to the inside wall opposite the woofer (to give a 30% increase in stiffness).
However, the inside of the cabinet has extensive windowpane bracing, which contributes to the cabinet’s overall solidity. The upper surface of the rectangular vent also doubles as an internal cabinet brace, just below the woofer. Right above the woofer is a “windowpane” brace. So even if the woofer panel is only 19mm thick (even thinner where it’s routed out for the driver mount), there appears to be sufficient solidity around the woofer. No harm, no foul.
The 6 ½-inch midrange driver is in it’s own isolated chamber within the cabinet. Both the midrange enclosure and the main cabinet interior are stuffed pretty densely with a fiberglass-ish (probably a flame-resistant polyester) material throughout, no doubt with the intent of reducing internal cabinet resonances and standing waves to a minimum. One gets the overall impression that this is a very inert cabinet that does not negatively intrude on the speaker’s sound.
Classic Four Internal View of Upper X-O, Cabinet Bracing, 1-inch Front Baffle
The tweeter is a ¾-inch anodized aluminum dome. In keeping with NHT’s avowed wide-dispersion design goal, the Classic Four is one of the few speakers on the market that uses a ¾-inch tweeter instead of the ubiquitous 1-inch dome. The midrange from 800 Hz to 4,000 Hz is handled by their truly excellent 2-inch dome midrange.
This is a very business-like speaker with the grilles off. The dome tweeter and dome midrange are mounted on a common faceplate adorned with a small NHT logo at the top. The faceplate itself has the feel of metal, but it’s actually a very dense bulk molding compound (BMC). Very strong, very dense, not “ringy” at all. An excellent choice of material.
Classic Four w/ Grille Off
The dome drivers have what appear to be clear plastic phase plugs/dispersion lenses in front of them, although NHT never states what they are or what purpose they serve. They could just be protection devices to ward off prying fingers, but usually these elements have an acoustic function as well. It’s interesting to see a ¾-inch dome tweeter again after all these years. Acoustic Research (the pre-eminent U.S. speaker company in the 1950s-1970s—they invented the dome tweeter in 1958) used various versions of their ¾-inch dome tweeter for decades in their top models, since the widest possible high-frequency dispersion was always a corporate design philosophy. But as I stated earlier, the 1-inch dome tweeter—with its vastly greater power handling and ability to cross over low enough to make a very effective 2-way system—has all but replaced the ¾-inch dome tweeter as the tweeter of choice. The Four’s tweeter used a neodymium magnet and a finned aluminum heatsink attached to the backside for added power handling.
Classic Four Midrange-Tweeter Assembly With and Without Anti-Diffraction Foam
Likewise the 2-inch dome midrange used in the Classic Four. It has what I would estimate is a rather substantial 6 mm (1/4-inch) cloth-roll surround, giving this driver surprisingly good excursion capability—which it needs, since it is crossed over at a relatively low 800 Hz. Compared to the usual 5 ¼-inch or 6 ½-inch midrange driver and 1-inch tweeter which would handle the 800-2,000 Hz range in a typical 3-way speaker, the NHT Classic Four will have incomparably broader dispersion. In fact, the Four is essentially omni-directional in the forward hemisphere, which gives the speaker a notably “unboxy” sound character and lends itself to great listener and speaker placement flexibility.
I have to admit to being somewhat surprised that the 2-inch dome midrange did not have any external heatsinking attached to its backplate. Considering that this driver is tasked with handling frequencies down to 800 Hz and will therefore be exposed to a fair amount of drive current, I expected some extra heatsinking would be called for.
Back of Tweeter-Midrange Assembly
However, this is just another of many instances where Monday-morning quarterbacking by people (in this case, me!) not involved with the actual design process make totally speculative comments that probably have very little to do with the reality of the situation. I am willing to accept on faith that NHT, a very solid engineering company, performed all the requisite power-handling and life tests on that midrange driver in situ and concluded that additional heatsinking, which is an added expense, was unnecessary.
Manufacurer’s Comment: The motor is quite substantial, so there is plenty of thermal mass. Also, the response is down 6dB at 800Hz and doesn’t reach full output until 1400Hz where it is out of the range where music has the most power concentrated. No one has ever blown one up by playing the speaker too loudly.
I was not able to remove the 6 ½-inch lower mid/upper woofer to get a look at its backside. It was just too snugly nested in the cabinet and prying it out would have resulted in damage to the Four’s beautiful gloss black front panel. I just didn’t have the heart. The frame seemed to be made of the same bulk molding compound (BMC) as the midrange-tweeter faceplate and the overall visual impression of the driver was in keeping with the high standards of the other drivers.
The side-mounted “subwoofer” in the Classic Four is one beefy driver. It may only be a woofer, not a subwoofer, but it’s well-executed. It’s a stamped-steel frame, but the frame is reinforced and vented in many areas to facilitate effective heat dissipation. I was quite surprised to see a magnetic shielding “can” over the magnet assembly. This was common in drivers 20 years ago to prevent the driver’s stray magnetic field from interfering with the picture when used near CRT televisions in home theater systems. Magnetic shielding hasn’t been needed for that reason since the advent of flat-panel TVs many years ago. One wonders why NHT still does this. It could be a way to increase the BL (a Thiele/Small parameter) of the speaker’s magnetic motor and optimize its sensitivity, since a shielded driver is often a dB or so more sensitive than its non-shielded counterpart. I’m just speculating here. It has what appears to be a 2-inch voice coil, a nice beefy-sized coil for a 10-inch driver, and that no doubt contributes to this driver’s sense of articulation and control.
Classic Four 10-inch Bass Driver Basket Vents
Classic Four Side-Mounted Bass Driver
Crossover, Grilles, Cabinet Finish
The crossover is a pretty conventional design, using standard parts. It’s split into two sections: The high-frequency section is mounted behind the tweeter/midrange assembly at the top of the cabinet, while the lower-frequency section is mounted behind the terminal cup in the lower part of the cabinet, near the 10-inch driver.
Lower Crossover Section (PCB in back of rear terminal cup)
The rear-facing rectangular vent for the 10-inch woofer is part of the cabinet construction, rather than a conventional plastic port tube, as in typical bass-reflex designs. It’s actually a clever design from many angles: The cross-section of the vent opening is large enough that “chuffing” is not an issue; NHT doesn’t have to buy or tool any molded plastic port tubes or flares as they would had they used a port tube; the vent’s construction serves double-duty as internal cabinet bracing around the woofer. These are the little hidden things that strong engineering companies like NHT do and the customer has no idea how intelligent the design is just by looking at the outside of the speaker.
Classic Four Woofer Cabinet Rout and Internal Vent Brace
The grilles were nothing special—just the standard plastic frames covered with stretched black cloth, and plastic “trees” that inserted into rubber grommet receptacles on the front baffle. Many speaker companies these days are using a slicker design of neodymium magnets hidden just beneath the surface of the front baffle, which then “grab” and precisely locate the grille frame (which would have reciprocal metal “coins” imbedded in the plastic frame to attract the neo magnets). More costly in both materials and manufacturing time, and not in keeping with NHT’s no-nonsense direct-to-the-customer business model.
My Classic Fours came in a gloss black paint finish. If a manufacturer is only going to offer one finish, it’s usually black, since black will go fairly well in almost any décor or room color scheme. Gloss black is hard to do well, since it’s very unforgiving of ripples, “orange peel” imperfections, tone and sheen variations, etc. A semi-gloss Satin Black is generally a better choice for a single-finish offering, since it’s easier to get it right, it doesn’t show smudges and fingerprints nearly as badly, and if done well, a Satin finish will still have an aura of luxury and high cost. Still, a Gloss finish, done correctly, looks great, no question. These were done correctly. They looked great. However….consider me a traditionalist. I’d love to see these speakers in a beautiful real-wood veneer finish, perhaps a nice Cherry or medium-toned Maple. But from a manufacturer’s standpoint, I certainly understand the appeal of offering and inventorying only one finish option. Any color you want…as long as it’s black.
Manufacturer’s Comment: NHT doesn’t do real wood veneer, since it’s not eco-friendly. We use an eco-friendly paint.
I set up and listened to the Classic Fours in a 2-channel music system. The room was a small-to-medium sized 17 x 14 x 8 ft. These are very good-sounding dimensions, since the length (17) is a prime number, and the height (8 ft) is not a whole number multiple of either the length or width. Therefore, these dimensions do not lend themselves to troublesome, additive bass/room resonances. The room has six 2 x 3 ft acoustic wall treatments staggered around the four walls (one centered on the front wall, two each at different heights on the side walls, and once centered on the rear wall between the two windows). There is a large sectional couch for seating and the floor is carpeted. Overall, the room is just slightly on the dead side of neutral, and it sounds excellent: solid, uniform bass, good imaging and detail, very little “ringing,” but live enough to let the speakers blossom out and fill the space with organic sound. Excellent recordings, especially of small-scale ensembles like jazz trio or solo piano, can sound almost live in this room. I have tremendous confidence that this room allows equipment to sound as good, or bad, as it can.
The Classic Fours were set up about 1 ½ feet from the wall behind them and about 2 ½-3 feet from the sidewalls. I experimented with placement by moving them closer to the wall behind them, but found that the balance got a little ‘tubby’ when the speakers were within about 6 inches to a foot of the wall. The speakers have extremely good horizontal dispersion and toe-in was minimal—perhaps 5º or so. Set up this way, the speakers threw a very solid, well-defined image with a good phantom center and, just as importantly, almost total immunity from stand-up/sit-down pickiness. That is attributable to the very close spacing of the two dome drivers (well within a half-wavelength at the crossover frequency of 4,000Hz), which enables them to act as a virtual “point source.”
The rest of the system is simple but straightforward, and very high quality. The pre-amplifier/power amp combo was Parasound’s New Classic 2100 pre-amp and 2250 power amp, rated at 200/385 watts per channel 20-20k, into 8/4 Ω loads, respectively. (Since the Fours are rated at 6 Ω, we’ll assume around 300 WPC.) The CD player was the NAD 545 with Burr-Brown DACs. Considering the modest size of the listening room, this is more than enough clean, distortion-free power to ensure that the electronics never intruded upon the listening sessions in a negative way. Speaker wire was simple 14 ga. twisted-end, inserted into the holes in the binding posts. Basic Monster interconnects between the pre/power and the CD/pre. Nothing lunatic-fringe about the connectors and speaker wire, and more importantly, nothing that could even remotely be considered a defining or distracting influence on the sound.
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Recent Forum Posts:
Shalmaneser, post: 1249767, member: 67624It's not easy to find better speakers for the price. But speakers are often a personal taste, so I'm sure there are other Brands/Models out there that folks would like. I was close with the original owners (Chris Byrne and Kenny Kantor) of NHT. Great guys.
You mean there's life after NHT? Where does one go for better price/performance?
DigitalDawn, post: 1249755, member: 78241You mean there's life after NHT? Where does one go for better price/performance?
I used to own 3.3's – great speakers with their 12" side firing drivers. I ended up selling them to a guy in Australia about 13 years ago.