German manufacturer Elac had a significant North American presence in the 1960s and '70s, primarily with its Miracord automatic turntables. While it eventually disappeared from the US market, Elac never ceased to be a player in Europe, where it eventually shifted its primary focus from turntables to loudspeakers.

When Elac decided to reenter the US market a few years ago, its success was hardly assured. Faced with hundreds of brand names and thousands of models fighting for attention, it hired veteran speaker guru Andrew Jones to improve the odds. In his previous work, first for KEF and then for TAD and Pioneer, Jones had built a solid reputation on designing well-received, cost-no-object speakers as well as high-value budget designs.

The results have been startling. Beginning with the aptly named Debut line, now in its second generation, and following up with the Uni-Fi series, Elac and Jones have made serious inroads in the sales of budget loudspeakers, reviving not only the Elac name but also an audio market too long smitten with blindingly priced speakers.

Nevertheless, Elac models have followed at higher, if not sky-high, prices. The company's current flagship line, Adante, comprises the AS-61 bookshelf model (and matching, optional, and recommended stands), the AC-61 center-channel, the SUB3070 subwoofer, and our subject here: the Adante AF-61 tower speaker ($5000/pair).

Design

Andrew Jones has used concentric drivers since his early years with KEF, and continues to favor them in all but his least expensive designs. For Elac they first appeared in the Uni-Fi range, and both the stand-mounted Adante AS-61 and the floorstanding AF-61 employ them as well.

In a concentric driver, the tweeter is positioned at the apex of the midrange cone, the latter acting as a waveguide for the former. The main benefit of a waveguide is to reduce the tweeter's dispersion at the low end of its range: Since the midrange driver (or midrange-woofer) typically has restricted dispersion at the top of its range, where it hands off to the tweeter, reducing a tweeter's dispersion in that region can smooth the transition between the two drive-units' outputs. A waveguide can also, but not always, enhance a tweeter's dispersion at the top end of its range. The AF-61's concentric tweeter is protected by a web-like screen, and is crossed over to the aluminum-coned midrange at 2kHz.

That 5.25" midrange drive-unit has a 2" voice coil, which leaves plenty of room inside it for the wide-surround, 1" soft-dome tweeter. To isolate it from the woofers, this concentric driver is mounted at the front of its own separate, sealed chamber with anti-vibration mountings.

While it might appear from the outside that the three-way AF-61 has three 8" woofers, it doesn't. What you see are three passive radiators. Each of these is partnered to its own 6.5" woofer, which operates invisibly, in an internal subenclosure. Together with two ports, that driver radiates into a second, smaller subenclosure that contains the passive radiator. The woofer and its ports never face the outside of the cabinet. Instead, their energy simply activates the 8" passive radiator, the "driver" you see. In other words: Each of the three visible woofers in the AF-61 is one of three separately enclosed woofer "systems," each comprising a 6.5" driver with two internal ports energizing an 8" passive radiator, the latter's diaphragm simply passing all of the bass to the outside.

This arrangement acts as an acoustical filter, limiting the bass output to below 200Hz and eliminating some of the expensive crossover parts that would otherwise be needed to achieve the same low-pass crossover with a conventional network (a high-pass filter is still required on the midrange). It also eliminates audible port resonances. Elac calls this design Interport-Coupled Cavity loading.

This isn't a new idea, but rather a variation of what was called bandpass loading when it was first used, decades ago. It never caught on big, likely because it's somewhat complex and expensive. Regardless of possible savings on crossover parts, a passive radiator together with a more complex cabinet will still cost more than a cardboard or plastic port. But the Wayback Machine tickling the dark recesses of my brain says that KEF did use it in some of its designs, which may be where Elac's Andrew Jones first worked with or became aware of it.

The cabinet structure required for this complex arrangement, with six separate internal chambers, not counting the small chamber for each midrange, makes for an extremely rigid enclosure, as rapping a knuckle on it painfully revealed. A heavy metal base plate, with outrigger corners and adjustable spikes, is also included. In addition, the AF-61s come with magnetically attached metal grilles. I used neither grilles nor spikes. The latter weren't sharp enough to penetrate the carpets that covered my hardwood floors, and if they had been I wouldn't put those floors at risk. I used a single run of speaker cable to each speaker, though biwiring or biamping are possible using each speaker's two pairs of high-quality binding posts. The available finishes are high-gloss black or white, or rosewood veneer (which looks more like dark walnut).

Setup

My listening area measures 21' long by 16' wide, with an oddly sloped ceiling at an estimated average height of 9'. This space is part of an open floor plan, with one of its 21' sides almost entirely open to a kitchen/breakfast area, which in turn opens into a dining room. The acoustic space is therefore far larger than the actual 21' by 16' listening area, which also accommodates the home-theater system used for my work for our sister publication Sound & Vision. That system includes two projection screens, but they're fully retracted when the main attraction is listening to music.

The room is relatively live, but apart from the kitchen, most of the floor area is covered with large, thick rugs. Shelves filled with books, CDs, and videos are on the back wall, several feet behind the listening seats.

I drove the Elacs with two channels (except where noted) of a Marantz AV8802A surround-sound processor, connected to two channels of a Proceed AMP5 five-channel power amplifier. In stereo operation, each of the Proceed's channels is driven by a completely separate power supply and transformer, not just separate secondaries from the same transformeras used here, it operates as two monoblocks built on one chassis. Proceed, now long gone from the market, was the home-theater branch of Mark Levinson, and 20 years ago, when new, the AMP5 sold for $5000 ($1000/channel), or about $7700/$1500 today, and was specified as producing 125Wpc into 8 ohms or 250Wpc into 4 ohms, all channels driven. Roughly the size of a high-end preamp, the AMP5 is small for a five-channel class-AB power amp but weighs over 100 lb. The source was a Marantz UD7007 universal BD player, connected to the Marantz pre-pro with a coaxial digital cable.

Except as noted, all recordings used were on CD.

Listening

The 52"-tall Adante AF-61s are moderately imposing in a domestic setting. I set them up about 9' apart and 11' from the main listening position, which put their front baffles about 4' out from the front wall. The center of the AF-61's concentric tweeter-midrange is 46" above the floor, considerably higher than the typical seated ear height of 3637". While my current listening ear height is a bit higher than that, it isn't close to 46". To compensate, I tilted the speakers forward slightly, and toed them in toward the listening seat. According to Andrew Jones, sitting slightly off the center axis on a concentric driver produces the lowest coloration, but I heard no clearly identifiable colorations in my setup.

While the initial listening tests were good, there was a distinct lack of impact below about 45Hz, obvious on material I know to have substantially extended bass. This wasn't entirely surprising, as it's also been true of some other speakers I've tested in this very large room. But my Monitor Audio Silver 10s have no problem producing convincing bass from the same positions, nor does an ancient pair of Energy Veritas v2.8s, the latter roughly the size of the Adantes.

When I performed a close-miked measurement of the AF-61s (fig.1) using an OmniMic measurement system from Parts Express (not nearly as sophisticated as the tools John Atkinson uses for Stereophile's speaker measurements, but excellent for basic measurements and setup), the response rolled off rapidly below 50Hz at about 18dB/octave (third-order). I measured all three of the front-mounted passive radiators, and they were essentially the same. Since bass frequencies are radiated from nowhere else on the AF-61, such as a port, these measurements indicates the bass capability of the speaker itself, with no help from so-called room gain. The single driver in Elac's Adante AS-61 minimonitor measured about the same when I reviewed that speaker for Sound & Vision, though the AF-61's three bass drivers' ability to minimize the well-known upper-bass floor-bounce dip (aka the Allison Effect), should offer benefits in overall bass balance and power handling.

Fig.1 Elac Adante AF-61, nearfield response of passive radiators (5dB/vertical div.).

When a speaker is designed, certain assumptions must be made concerning the room in which it's likely to be used, particularly the room's size. All rooms affect the bass, including boosting the lowest frequenciesthe room gain. The bigger the room, the lower the room gain, which is why a speaker used outdoors typically has anemic low bass. Designers who assume little room gain extend the bass as far as the design's size and budget allow. If a smaller room with a lot of room gain is assumed, the designer will keep the extension in check. I don't know what assumptions Andrew Jones made in designing the AF-61, but given the likely international appeal of the speakers, I suspect a room as big as mine, with little room gain, wasn't high on the checklist.