Rockport Technologies Merak II loudspeaker & Sheritan II subwoofer
While the Merak-Sheritan concept resembles that of Wilson Audio's two-box WATT/Puppy combo, Rockport's execution of it is quite different. The WATT was originally designed as a recording monitor of manageable portability. The Merak II, at 20" tall, 22" deep, and weighing almost 150 lbs, has a swelled head by comparison. Putting it atop its integral stand or a Sheritan II bass module is best accomplished by two people.
The rear-ported Merak features a custom-built 7" woofer from Denmark's Audiotechnology (founded by the same man who established Dynaudio and ScanSpeak), and the same 1" Dynaudio Esotar silk-dome tweeter that's used in Rockport's Antares speaker, which I reviewed in the August 2002 Stereophile. Like every other tweeter, this one has its admirers (robust motor, high power-handling capacity, smooth response) and its detractors (mass too high, "slow," so-so off-axis response). I loved its smooth, tactile performance in both Rockport's Antares and Merlin Music Systems' VSM Millennium (see review in the September 2001 Stereophile).
The cabinets of the Merak II and the Antares are built with the same fanatical attention paid to controlling resonances. Payor describes this enclosure as "essentially...an inertial reference, subsequently, there is virtually no tendency for it to vibrate." Two years ago, John Atkinson's extraordinarily low measurements of the Antares' cabinet resonances backed up Rockport's claim.
Briefly, here's how the Merak II is built (see my August 2002 review for a more detailed description of the process): A female mold is sprayed with an industrial-strength version of Pam, then laid up with layers of resin reinforced with glass fiber, much like the body of a Corvette. Each layer is allowed to harden before the next is applied, until there is a "high tensile strength" shell, 10mm thick.
The same reinforced-resin process is then applied in reverse to a smaller, male mold. When that shell has hardened, it is pulled off the mold and inserted into the larger one. A goo of high-density, high-hysteresis-loss, mineral-filled epoxy—specially developed for Rockport—is then poured between the two shells, to form a 30mm-thick core bonding the shells together.
The result is a five-sided, molded monocoque cabinet with a host of features the above description doesn't touch on. Internal braces are built into the mold, each drive-unit has its own chamber, and an integral molded rear port (the port lining itself is machined from thick aluminum) is part of the separately laid-up cabinet rear, which is eventually mated with and sealed to the five-sided box. There is only one seam in the entire structure.
Rockport claims the epoxy core material is three times as dense as typical medium-density fiberboard, while the outer shell is three times as stiff and dense as the same thickness of MDF. The composite "cannot be matched by single-material construction," says Rockport, because no single material—whether MDF, or sheets of an acrylic resin such as Corian or Fountainhead—has the same combination of high mass, high stiffness, and high damping. Rockport's molding process also allows the Merak's cabinet geometry to be optimized for driver placement, reduction of standing waves, and other design goals that would be difficult or impossible to attain using normal woodworking techniques, according to the propaganda sheet Payor faxed me.
The final finish is another Rockport magilla. A primer of polyester is followed by much hand-sanding, an epoxy sealer, a urethane base, and, finally, a clear coat. The standard finish is a glossy black subtly flecked to make it look (to my eyes) like the cosmos; any automotive color that suits your fancy is also available, at extra cost. The front baffle is fitted with treble-damper felt from Steinway & Sons, as in the Antares. In fact, it would be fair to say that the Merak II is basically an Antares cut off at the knees—no, the ankles.
All of this attention to the minutiae of design results in a cabinet of singular rigidity and integrity—and, if the Antares is any indication, a freedom from resonances that puts it in a class by itself. I haven't come across anything like these cabinets. If you're asked to shell out $19,500 for a pair of two-way speakers on stands, you're entitled to heroic construction in the service of performance and fit'n'finish perfection. With the Merak II you get both, though their looks won't please everyone. "Darth Vader meets L.I. Lucite countertops" was one friend's reaction to the Antares. The Merak II is more like Darth without the Lucite.
Rockport supplies stands made of solid, triple-layered MDF members, doweled and glued at all joints. These, too, are claimed to be inert, the speaker/stand interface enhanced by the stand's cradle-like design, which couples with the speaker's bottom-surface protrusion. This interface lowers the entire assembly's center of gravity, thus making it more stable. The cabinet comes fitted with four stiff Delrin interfaces that sit on damped, urethane inserts built into the stands.
The crossover, built on a base of ½"-thick aluminum and then potted, is housed in a recess in the stand. It connects to the Merak II via a "pigtail" that hangs from the Merak's back and is terminated in a Neutrik Speakon plug. Andy Payor claims the relatively low crossover point of about 2kHz is made possible by the Esotar tweeter's ultra-low resonant frequency and its high power-handling capacity.
The usual places?
Placed where most speakers sound best in my room—a little more than 2½' from the front wall, toed in toward the listening position, and 8' apart—the two-way-on-steroids Merak IIs presented an imposing physical picture. They sit low in the saddles of their dedicated stands, putting the listener's ears midway between the tweeter and woofer. The big Wavac SH-833 tubed monoblock power amps were still in my system (see review in the July 2004 issue), so that's how I first listened.
It was a match made in hell: way too warm, and not particularly well controlled in the midbass. Fun though they may be, the Wavacs' quirky sonic and test-bench performances don't exactly make them reliable partners for a loudspeaker review (which is not the same as saying that, with the right speakers, the Wavacs might not work magic). I then hooked up the Music Reference RM-200, which sounds and measures more linearly despite it having a tubed output stage. It proved a better match for the 87dB-sensitive Merak II, but still not what the speaker required, in my opinion: a big, solid-state amp with a high damping factor.
With the Musical Fidelity Tri-Vista kW monoblocks in place, the Merak IIs opened up, tightened up, and began to sound as I imagined their designer intended them to sound—except for one curious thing. Whereas most speakers require fine-tuning of placement to maximize their bass performance because of a suckout in my room, even with the solid-state amps, the Merak IIs put out too much bass—and I mean real bass, comfortably down to around 40Hz, which covers more of the musical picture than many audiophiles suspect. There I was, for the first time in the five years I've used this room, actually trying to reduce a speaker's bass output. When placed farther forward in the room than I usually position speakers, the Merak IIs delivered their weighty message.
Don't be put off by the Merak II's seemingly demanding nature. Often, a genuinely high-performance product requires more work, and ultra-careful choice of associated equipment, before you can get the most from them. But when you do, you'll hear things lesser speakers can't begin to deliver.