D-Box Iliad Home Theater Speaker System

      Date posted: February 24, 2004

D-box Iliad T1 Home Theater Loudspeaker

Sizes: T1: 39 3/8″H x 8″W x 13 1/8″D;
C1: 22″W x 8″H x 12″D; B1: 16″H x 8″W
x 13 1/8″D; S1: 23″H x 14″W x 19
3/16″D (all w/ grilles)
D-box Iliad S1 Subwoofer

Sugg. Retail (CAN): T1: $1099.00 pr;
C1: $469.00; B1: $599.00 pr; S1 Sub:$879.00
Total System Cost: $3046.00 (CAN)
Manufacturer: D-Box Technology,
2172 rue de la Province, Longueuil QC
J4G 1R7 (450) 442-3003 FAX 442-3230

(Reprinted from the Winter/Srping 2004 Audio Ideas Guide)

      The Iliad system has been demonstrated many times at shows over the past couple of years, to some extent playing second fiddle to the company’s seat-shaking Odyssee programmed deep bass enhancement system. But on the several occasions I’ve sat down and vibrated, I’ve noticed that the overall heard sound was pretty impressive and powerful too. D-Box has always been a subwoofer company, and readers may recall our cover-story review of the mighty Mammoth (Almanac 98, Vol. 17 #3); and my wife’s little system upstairs consists of a pair of the original metal-encased D-Box powered speakers, a classic of its genre, and a portable CD player.

     The Iliad cabinets, which are made in Asia, have double front baffles that reinforce the front surface, and, like those of the Energy Connoisseur series, stand out to allow a close fit of the grille covers, and to minimize diffraction. The enclosures are made of both MDF and particle board, and are internally braced. All are front-ported designs.

     The drivers, custom made for D-Box by Audax of Sweden, consist of a 6.5″ woofer/midrange with “damped composite cones, rubber surrounds and high density polymer frames”, while the tweeter is a “1″ textile” driver “with wide-dispersion Zamack faceplate”. Crossover in all cases is a “2-way, 12-element modified Linkwitz Riley configuration”. All but the B1 use dual 6 1/2″ drivers, except, of course, the S1, which uses a “12″ woofer with HD-A composite cone”. It is powered by a 110-watt class A/B amplifier capable of 350 watts of peak power, and has the usual adjustments for level, crossover point, and phase, with speaker and line level in-puts.

     It’s quite a handsome system, with its silver grey and black accents, but far from invisible, and will prefer a fairly good-sized room. There is also a Redwood vinyl finish available.

     Some notes about the goals of the Canadian D-Box engineering and design team from their literature: “Modest only in price, the T1 will delight the senses and warm the spirit…C1 styling and performance are perfectly matched to other Iliad models and it delivers dialogue and other center channel effects with stunning accuracy and placement… the Iliad Super Bookshelf speakers deliver natural, well-balanced sound with any program material”.

     This all may sound like your average speaker hype, but the choice of words does seem to reflect the measurements, and a complex set of curves they are. At top is D-Box Iliad HT System Response D-Box Iliad Impedances, top below 1 kHz, Phase grouped below the Summed Axial Response (SAR) of the T1, overlaid at left with the S1 subwoofer curves at highest, middle, and lowest crossover settings. All of these curves are Pink Noise Sweeps (PNS), those for the front, centre, and rear vertically averaged over the height of the driver arrays for each shown measurement at 0, 15, and 30 degrees laterally, with an additional 60 degree curve for the T1 front speakers. These extensive measurements (enlarged for clarity) give an excellent picture of what you will hear from this system.

     The T1 curves (the group just under its own SAR, which adds these together) shows excellent closeness between 0 and 15 degrees , with about a 4-5 dB dropoff at high frequencies at 30 degrees off axis at 10 kHz. This controlled dispersion will help focus the front radiation, and the 7-dB-down 60 degree curve minimizes side wall reflections. These speakers will offer clean, focused sound in most rooms, with just a little extra definition above 5 kHz, and a slight droop in the midrange, which will make the sound less aggressive in a smaller space. Getting back to the SAR at top, its overall response across the 60 degree axis is +/-2 dB over much of the range, with a tiny bit of added warmth in the 300-Hz region, and a smooth, controlled rolloff below. Bass is down 3 dB at 100 Hz, but plateaus to 50 Hz, down only 5 dB at 35 Hz, good extension for these modestly priced towers.

D-Box Iliad Center Channel

      Below, we see curves for the C1, which is a so called D’Appolito configuration, with the 6 1/2″ drivers flanking the tweeter, which is vertically offset a bit, the two ports below it. I mention this, because this driver array does not mimic the typical such configuration, in that as we move off axis in the measurements we find less of the usual midrange dip; it is seen at 15 degrees, but notice how the 30 degree curve, while 5 dB down, is almost a straight line (the flattest of all the C models) from 1 to 15 kHz. This means that dialogue will indeed be well heard by those at either end of the sofa, the 15 degree curves less important here since they represent less than the width of an average human body. In other words, these measurements predict an unusually articulate centre speaker over a broad listening axis.

     The bottom set of curves chronicles the B1 surrounds, which also appear to be excellent small bookshelf models on their own, raising the possibility of building a full system around these and the C1/S1s at a lower cost. The B1 curves match those of the C1 very well in the upper octaves, ensuring tonal uniformity, with excellent bass extension for size, down only 5 dB or so at 50 Hz, but rolling off steeply below. They are also a little more neutral in the upper bass-midrange area between 200 and and 1500 Hz. In the top end, dispersion is well controlled at 30 degrees, making for very accurate effects placement.

D-box Iliad Impedance

     The impedance and phase curves look like a bit of a jumble, but the impedance traces are those with the bump below 100 Hz, and are very smooth through the crossover region. The B1’s impedance is a little higher because of the single bass/mid driver, and its sensitivity is about 2 dB lower acoustically for the same reason. The phase curves, the lower group below 1 kHz, are very similar, with virtually no phase shift through the crossover, predicting at least excellent imaging all around, and easy loads to drive in all three cases. The close grouping of all the phase curves above 2 kHz is a clear indication of outstanding crossover design achievement. And, finally, some words about the S1 subwoofer. The philosophy at D-Box has been, over the years (and we’ve reviewed numerous models in that time) has been to design for speed as much as for extension; that is, faster, tighter bass is better than slower, deeper low frequencies.

     This modestly priced sub errs, perhaps, a little more on the speed side, rolling off fairly quickly below 50 Hz with the crossover set to 160 Hz, +/-2 1/2 dB over this range. I should note here that the level differences of the crossover settings, roughly 4 dB per curve, present a true level difference with each setting; and this results in a trend to smoother response at lower crossover settings. Thus we see greater extension at the mid point of the rotary control (70-80 Hz) +/-2 dB from 40 to 150 Hz, and at the lowest 40-Hz setting, +/-2 1/2 dB from 20 to almost 150 Hz. This latter was setting was very close to what I found optimum with this system, offering the best combination of speed and extension. As an aside, it’s nice to see D-Box offering both, but you have to crank the sub level by a good 10 dB relative to the highest crossover setting. Don’t worry, it can take it.

D-Box Iliad B-1 bookshelf speaker/surround

     The special design care in this system translates in listening to an especially articulate overall presentation, with excellent sparkle at the corners, and a solid middle dialogue and effect presence. Imaging, across the front and from the surrounds is very precise, this helped by the control of side wall reflections; these also allow clear side soundstage reproduction as well, with soundfields stretching among all the speakers. The subwoofer, when optimally set up (with the crossover at or near 50 Hz), has great power and bottom reach, as well as good transient speed.

     This is a very good home theatre system, but also offers sufficient refinement to be an excellent music reproduction system, a bargain at its price. In sum, the Iliad is suitable for bigger rooms and bigger sound than the Totem Dreamcatcher reviewed last issue (Fall 03, Vol. 21 #4), and is one of the best $3000 complete HT systems we’ve heard. It can also be a really good $1500 full range smaller room music system with the B1/S1 trio. What more can you ask for?

Andrew Marshall

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