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.
Design Overview
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.
Double-Boxed Packing
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.
Wide dispersion was a stated design goal for the Classic Four and NHT went about it the right way.
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.
The black gloss finish looked great on these speakers.
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.
Set-Up
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."
Associated Equipment
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 ? loads,
respectively. (Since the Fours are rated at 6 ?, 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.
http://www.audioholics.com/tower-speaker-reviews/nht-classic-four-speaker-review
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