NHT’s all-new Xd system gives us a tantalizing glimpse into the future of loudspeaker design—correction, make that digital loudspeaker design. NHT (Now Hear This), the lauded Benicia, Calif., speaker manufacturer, recently joined forces with DEQX, a firm that specializes in digital speaker correction techniques, and PowerPhysics, a leading developer of digital power amplifiers, to create the new Xd speaker system.

Frankly, I am surprised that NHT resisted the temptation to premiere the technology in a no-holds-barred tower speaker and instead built the devilishly compact XdS satellite speakers and XdW subwoofer. The XdA digital processor/amplifier serves as the brains of the outfit. For this review I am using the stereo, 2.1-channel version of the Xd, but it can be expanded for home theater service with additional XdS satellites, XdW subwoofers, and XdA amplifiers. The blond faux wood/burgundy color scheme is stunning and a satin/gloss black finish is also available. The satellites can be wall-mounted or perched upon NHT’s tautly bowed speaker stands that harmoniously play off the satellites’ sensually curved baffle. You have never seen anything quite like it.

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The XdA digital amplifier provides digital crossover processing for the XdS satellites and the XdW subwoofer. (Click image to enlarge)

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Conventional speakers rely on a crossover network to route the treble frequencies to the tweeter and the bass range to the woofer. Depending on the details of the speaker’s design, these all-analog networks can be relatively simple or quite intricate, but they always convert some of your amplifier’s power into heat and add minute levels of distortion to the speaker’s sound. NHT and DEQX have a better idea: an all-digital crossover that does not waste any watts, and better still, is designed to extract the best performance from the XdS satellite’s 5.25-inch magnesium-cone woofer and 1-inch aluminum-dome tweeter. The digital crossover’s prime directives are to deliver ruler-flat frequency response and improved power handling while minimizing distortion in the woofer and tweeter—all so the Xd can play louder and produce more accurate sound than conventional speakers.

This is all very nice, but when the line between the sound of a real Stradivarius violin and the sound emanating from the speaker is indistinguishable, the folks at NHT can throw one heck of a party. The Xd is not quite there yet, but I have no doubt that NHT’s engineers will be working on closing the gap. And thanks to the upgradeable nature of the XdA’s processing software, the system you buy today may deliver even better sound a year or two down the road. Another plus: the Xd is a “plug-and-play” system unencumbered with user adjustments or pesky setup menus.The XdW subwoofer features two 10-inch woofers and a 500-watt PowerPhysics amplifier; the sub’s frequency response tailoring and crossover are handled by the XdA. The XdW’s side-mounted woofers effectively cancel the cabinet’s vibrations—place your hand on the curved top and you will feel no shaking. The real payoff to the design gambit is that the quiet cabinet will minimize the amount of bass transmitted to the floor or the rooms below the subwoofer. If you live in an apartment, your neighbors will love your Xd almost as much as you do.
 

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Thanks to the XdA’s extremely steep crossover slopes (about 100 dB/octave), NHT’s engineers did not have to compromise sound dispersion to achieve high power handling. (Click image to enlarge)

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The XdA digital amplifier is fitted with four cool-running PowerPhysics 150-watt power modules to “bi-amplify” two XdS satellite speakers (one module per woofer and tweeter). The XdA’s rear apron hosts a wide range of connectivity options. From left to right, there’s a USB port available for software upgrades; a microphone input that will come into play with the upcoming room correction system; RCA and XLR inputs that you hook up to your stereo preamplifier or surround processor; outputs for two XdW subwoofers; 12-volt triggers for remote power on/off; an accessory jack intended for use with the upcoming wireless subwoofer transmitter that will eliminate that long cable in your system; and color-coded speaker jacks that accept the special banana jacks that mate with the XdS satellites.

You cannot realize how much distortion you are used to hearing from your audio system until it is gone. Audiophiles love to throw words like “resolution” and “transparency” around, but to express those concepts more directly, we desire a sound that is extremely detailed, and we want to hear into the deepest recesses of the recording. These events certainly occur when I play Norah Jones’ Come Away With Me CD through the Xd: She sounds like she is in the room with me. Thanks to the XdW subwoofer’s proficiency, John Hiatt’s bare-fisted rock and roll has the kick I usually get from larger speakers. Jazz legend Max Roach’s all-percussion ensemble M’Boom displays the digital speakers’ talents better than any other disc I try. The Xd can reproduce the complex textures and dynamics of the band’s marimba, timbales, xylophone, tympani, vibes, bells, gongs, and drum set with startling realism. The digital system clearly has the resolution issue covered.

Is the Xd perfect? Well, no. The satellites and subwoofer are not as seamlessly matched as I would like. On some recordings, the bass sounds too lightweight, but on most discs the low-end is excellent. The digital technology can work wonders, but I cannot tell you the 10.3-inch-tall satellites will satisfy those of you lusting after a big-speaker sound; the Xd is no giant killer. And at night, when my apartment is at its quietest, I notice a faint background hiss coming from the XdS satellites. It does not intrude on the music, but I always hear cracking sounds for a few seconds when I turn the XdA amplifier on. I suspect NHT is working to quell the noises, but they should have fixed this before shipping the product. Please be aware that the Xd is a closed system—you cannot substitute any part, say the XdA amplifier, for another amplifier, or the satellites or subwoofer for that matter. An all-Xd system is the only available course.

Over the coming years I have no doubt that we will see more and more manufacturers developing digital solutions. The little Xd could be the start of something big.

PRICE: 2.1-channel Xd, $6,000; 5.1-channel
Xd, $14,850; 6.1-channel Xd, $15,600

CONTACT: 800.648.9993, www.nhthifi.com