The NHT Classic Four Surround Sound Speaker System Page 2

Placed where they had to go in the room, rather than where they might provide the best bass performance, and saddled with handing full-range bass and the LFE channel, the Classic Fours, predictably, produced an overabundance of deep bass and some lower mid-bass bloat. "Predictably," because along with what my ears told me, my time with the R.A.B.O.S. bass equalization system built into Infinity's subwoofers demonstrated that the left corner of my room, where the subwoofer must be placed (close to where the left front speaker also must go), has a significant bass-thickening "bump." Moving the speakers further into the room and away from the corner would have helped, but that move was impossible because of the television's location and, more importantly, because my wife wouldn't allow it, so in came the X2 crossover and A1 amplifiers.

Your need to incur the extra cost of the amps and crossover will, of course, be determined by your placement possibilities and room acoustics as well as the bass- equalization capabilities of your electronics. If driving the Fours full range works well for you, you'd run the Fours as "large," routing both bass frequencies and the LFE channel into the front channels.

Listening With the X2 Crossover and A1 Amplifiers
Bi-amping the Classic Four requires removing the speaker "jumpers" that connect the bass driver to the upper three-way system and routing the front left and right channel outputs into the X2 crossover. This is easily accomplished with a system of separates consisting of a preamp/processor and multichannel amplifier. It can also be done with an AV receiver that offers the flexibility of both preamp output and power amp input connections. You'd run the pre-pro (or receiver's) front L/R preamp outputs full range into the X2's high-pass filters to remove lower bass from the signal, then feed the X2's output to the front L/R amplifier channels (or the receiver's L/R amplifier inputs). If your AVR only offers line "outs" and not amp "ins," you might be able to use the receiver's internal crossover to filter out lower bass, but for the best match make sure your AVR's crossover slopes match the 12dB/octave slopes of the NHT system.

Either way, this results in the front L/R channels' amplifiers feeding a bass-limited signal to the Classic Four's upper speaker terminals, while the X2's outputs feed lower bass frequencies to the A1 amplifiers, which drive the Four's side-firing 10" woofers. There is also a line level connection that can be used from a pre/pro or AVR's LFE output to the X2 allowing the Classic Four's to reproduce LFE bass.

While the A1 amps are designed to stack on top of the X2 (they include downward firing lighting to illuminate the X2's control panel), running speaker wire across my living room floor was a non-starter. Fortunately, when I installed speaker wires across the room via the attic, I also ran a long pair of interconnects, which I used to run the X2's line outputs to the speakers, next to which I placed the compact A1 amps. The lights on the amp may be dimmed or turned off altogether.

Once everything is connected, the X2 offers nearly unlimited flexibility. There are front-mounted master and LFE gain controls, as well as others for low pass filter, phase and boundary EQ controls. The rear panel includes a three position, rear-mounted high pass filter and a two-position subwoofer gain switch.

Without spilling too much ink on the specifics, using these controls and some revealing musical and cinematic material, I was able to dial in the Four's 10" woofers to obtain impressive bottom to top tonal balance with robust, musical bass, stomach crunching low frequency effects and what can only be described as "big sound."

Considering that the cost of the amps and crossover totals $1,150, which is less than the cost of many subwoofers, I'd say it's a great investment and it leaves the front of your home theater space uncluttered by an outboard subwoofer. If you insist on sub-25Hz performance you'll still need a dedicated outboard subwoofer. But I never felt starved for bottom end with this system.

The Classic Sound
Despite claims to the contrary by some manufacturers, getting a big, dynamic "theater-like" sonic experience requires moving a lot of air—I don't care how small the room. Moving that much air requires big drivers. The bigger the better. With this Classic system, you get a pair of 10" subs upfront and you get 6.5" mid-bass drivers all around, including a pair in the center channel speaker, for a total of six. This system moves a lot of air and it produces a big, robust, enveloping soundfield. Rest assured that you can play this system at very high SPLs in medium to large rooms without straining its capabilities, and I'm sure it will coast easily in a small environment.

When you hear the Classic Four based system, even with your eyes closed, you will have no doubt that you are in the presence of a big-ass multichannel speaker system. Yet because of its compact three-way basic module, and the side-firing 10" drivers mounted in the Fours, the Classic system neither occupies a great deal of floor space nor steals focus from the rest of the furniture in your room. Whether or not the gloss black look appeals to your eyes is a personal consideration. While natural veneers or even well done vinyl might be more living room friendly, NHT's chosen finish is both attractive and clearly cost effective.

While bass performance is room dependent, I feel safe in saying that the Classic's bottom end, along with being well extended and dynamic, is on the somewhat under-damped and thick side. If you're looking for "light to the touch" bass, you won't get it here. If you like it "whompin' and stompin'" and physical (yet convincingly textured and reasonably well controlled), look no further. I can't think of another $1,800 a pair speaker system that delivers bottom end like these do.

Curiously, despite the 6.5" midbass and the generous 2" aluminum dome midrange drivers, I found the Classic system's overall sound somewhat withdrawn in the upper midbass/lower midrange region and cool sounding in the midrange; a combo that no amount of subwoofer fiddling could ameliorate. While it was possible to thicken and fatten the bottom end using the X2's controls, there was no warming up the midrange. Thus the system's ability to produce tactile, well-textured, harmonically complete and delicate images was somewhat restricted compared to some other (more expensive) speakers I've auditioned, including the less-than-stellar measuring Sonus Faber Domus system.

The system's top end, while impressively extended and smooth, also sounded cool, reserved and slightly mechanical. I am not one who equates metal drivers with "metallic" sound, but in this case that conclusion was inescapable. One reason this review took a long time was to ensure that the tonal balance wasn't the result of insufficient break-in.

Over time, the tonal balance remained consistent, although changing associated electronics did produce notable differences. Despite the system's relatively low price, its moderately low efficiency (86dB for the Four, 87dB for the Three and Three C) means it requires a healthy reservoir of power to deliver the goods—especially if you want high SPLs.