RBH MC-6CT Loudspeakers
 "Speakers
are difficult," proclaimed a knowledgeable audiophile a long time ago. But to a kid
rapidly developing a love for all things audio, the only difficulty I had with speakers
was that I couldn’t afford a pair that was worth a sonic damn. My flea-market
specials -- vinyl-covered 12-inchers, complete with volume pots for the midrange drivers
and paper tweeters -- produced a sound that, even to my uncultivated ear, bore little
resemblance to real music. But I readily devoured all the audio magazines had to say (this
was pre-Internet), and I believed that there were better speakers out there. In my
mind’s ear, I could hear those multi-driver behemoths in all their glory. All I
needed was the dough to pick up a pair and cruise into sonic nirvana.
Yes, you can get good sound out of a $1000 pair of boxes,
and yes, the RBH MC-6CT does deliver the goods at its asking price of $999 USD per pair.
But before you surrender your hard-earned green, you’ve got to know just what’s
sonically important to you, and which compromises you can live with.
No loudspeaker can be all things to all people. Speakers
are primarily mechanical devices, with parts that move to excite the air around them.
Compare their operational parameters to power amplifiers, for example, which, save for the
power supply (i.e., AC, or, in some rare instances, DC), operate under largely
controlled circumstances independent of room acoustics, temperature, humidity, and the
choice of materials used in construction. But more than any other piece of audio gear,
speakers involve design compromises, and interact with and are sonically affected by their
surroundings and choices made in their design, including but not limited to materials and
bass-loading principles. As such, they come in a wide variety of flavors.
A lot of cash can buy a lot of speaker (though I’ve
heard exceptions to this general rule), and the law of diminishing returns certainly
applies. But even a megabuck speaker will necessarily reflect its designer’s
understanding of what constitutes great sound and how to achieve it. If, at some price
point -- say, $100,000/pair -- the theoretical ideal of reproduced sound could be
achieved, then all $100,000/pair speakers would sound alike. While a comparison of
stratospherically priced designs is beyond the scope of this article, suffice it to say
that, even at that end of the price scale, the sonic signatures of different speaker
designs vary as greatly as they do among $1000/pair speakers.
Enter the RBH MC-6CT
Each RBH MC-6CT came double-boxed, well protected from
ne’er-do-well shippers. Unpacking them revealed a well-constructed pair of black
boxes finished on the sides, top, and bottom in real-wood veneer. Fit’n’finish
were very good for $999/pair -- actually, good period. Noteworthy was that the deeply
figured, well-grained veneer was way beyond the quality of wood (when real wood is used at
all) usually found at this price. Each speaker weighs 55 pounds, measures 40"H x
7.75"W x 11.5"D, and cuts a handsome profile.
An informal knuckle rap test of the side, top, front, and
rear panels of each speaker revealed fairly solid construction; box resonances should not
come into play to the degree that they do in less-well-constructed designs. I’m
particularly sensitive to box resonances -- my Magnepan MG1.6/QR planar speakers have no
boxes at all, and their bass is commensurately free of the woolly, boomy quality that
vibrating MDF can contribute to the sound. But at least partly for the same reason, the
boxless Maggies’ bass can lack a little weight. Not that the Maggies are bass-shy --
they can just be a little, well, lacking in slam. Choices.
The RBH is an acoustic-suspension design, which means its
cabinet is sealed. Nowhere is there a port, slot, or other means of egress for the air in
the box. The acoustic-suspension principle of bass-loading operates as follows: Air
trapped in a sealed cabinet creates a cushion behind the woofer that acts to control the
pistonic motion of the driver above its resonance frequency, and limit the driver’s
motion below that frequency.
The 2.5-way RBH has a 1" aluminum-dome tweeter and
three 6.5" aluminum woofers. The two lower woofers are strictly for bass duty, and
are rolled off at 12dB/octave above 200Hz; the third 6.5" cone is actually a
mid-woofer that overlaps the range of the two lower woofers while providing sonic
information up through the midrange; the tweeter takes over at 3kHz. While RBH could have
designated the mid-woofer for midrange duty only, they chose to use a third woofer to
achieve a more powerful response down low.
The changes from the first generation of the MC-6CT include
a "faceplate" around the tweeter, but the most interesting change made for the
second generation is that RBH has done away with the swiveling tweeter of yore in favor of
a more ordinary, stationary tweeter. While this move removes some of the placement
flexibility inherent in the earlier design, I’m acquainted with one owner of that
model who tells me that he regularly spends time at each listening session searching for
the ideal positions of speaker and tweeter at which the midrange and treble information
blend into a seamless sonic portrait. He also tells me that, at a certain point, this
exercise ceases to be gratifying. A well-designed crossover can and should address what
otherwise might be accomplished by a swiveling tweeter. I like the new version's fixed
tweeter just fine.
System, positioning, and the like
I set up the RBHs in my reference system, which comprises a
Sony SACD ES-222 SACD/CD player, a B&K PT-3 preamplifier-tuner, and a B&K ST-2140
power amp. Speaker cables were original 12-gauge Monsters biwiring each speaker.
Interconnects were Kimber PBJs all around. I broke the RBHs in with 50 hours of FM
interstation noise played at a moderately loud level. The final speaker positions were
30" from the front wall to the back of each cabinet and 80" between the
speakers’ inside walls. I sat 8’ away from the fronts of the speakers, my ears
at tweeter level, the speakers toed in about 7 degrees toward me.
I turn on some music and forget the day
Because the MC-6CT is an acoustic-suspension design, I
thought I’d begin with some material that would let me hear and understand its bass
response. The Christian McBride Band’s Vertical Vision [CD, Warner Bros.
48278-2] shows the bassist at his best. The playing is loose yet controlled, and
wonderfully expressive. The RBH was highly adept at revealing bass textures, with the
right blend of leading-edge attack and harmonic decay to make bass notes crisp and
satisfying. On "Technicolor Nightmare," for example, McBride lays down a heavy,
driving groove that the RBH timed very nicely, thank you -- there was no blurring or
smearing of the bass notes, as I’ve heard from lesser designs. However,
McBride’s bass on this track, and on this disc in general, has a warm tone (it
borders on the too warm, in my opinion) that the RBH did not completely capture.
The speaker’s rendition was ever-so-slightly to the leaner side of things. This kind
of slight subtraction didn’t bother me, and is definitely preferable to the more
common thickening and blurring of notes heard from lesser designs.
I then thought I’d try some old-school metal to hear
how well the RBH could head-bang. Mercyful Fate makes Led Zeppelin look like Catholic high
school girls. I rate "Evil," from their 1983 release Melissa [CD,
Roadrunner RR 8770-2], one of the most intensely powerful rock songs ever recorded. The
RBH delivered the power and emotion of "Evil" intact. The guitars were clear and
present, and crunched with enough power to get my blood going. The drums and bass hung
together correctly -- no overhang or other aberrations to disrupt tempo or intensity. And
King Diamond’s vocals were handled very well. There were no nasal colorations, no
problems with clarity, and diction was highly intelligible. Yes, I could have asked for a
little more lower-midrange heft -- a little more chest, a little less throat.
The RBHs had no problems when I cranked them to high levels
in my medium-sized listening room, nor did they have any problem reaching those levels
with a solid 140W behind them. If you listen loud, let ’em have 100Wpc; for more
moderate levels, 50Wpc should suffice.
King Diamond’s demonic verses gave way to Tony
Bennett’s considerable vocal gymnastics. On Perfectly Frank [CD, Columbia
52965], Bennett covers two dozen Frank Sinatra classics. Hearing these covers, it’s
not hard to understand why Bennett was Sinatra’s favorite singer. On "Time After
Time," Bennett stretches notes as if a whammy bar is attached to his vocal cords, but
it all sounds so natural, so beautiful. The RBHs brought Bennett into my room and allowed
me to understand what makes him a great vocalist. All of his inflections were intact, and
the singer’s sense of joy shone through. The separation and placements of instruments
were good, although the soundstage depth was only okay. On "Nancy," the slight
leanness in the lower midrange that was apparent with the Mercyful Fate album did not
manifest itself, but a coolness in the lower treble resulted in a little too much
sibilance. Toeing the speakers out by a couple of degrees somewhat alleviated this, at the
expense of a slightly flatter soundstage. Warmer-sounding amps and/or preamps and/or
cables should go a long way toward taming this mild transgression.
A jazz classic and favorite of mine is the Dave Brubeck
Quartet’s Take Five [CD, Columbia/Legacy 65122]. The separation between
instruments in the title track was good through the RBHs. Joe Morello’s hi-hat and
snare were cleanly rendered, albeit with a little dryness in the lower treble. The bass
drum and bass guitar had proper pitch and good definition, although ultimate extension at
the bottom was missing. Morello’s bass drum had nice thump and decay, but the full
bloom was not completely portrayed. The RBH is specified as being down by 3dB at 45Hz, and
that sounds correct in my room. That’s fairly deep bass, but not truly full-range --
the lowest note on a bass guitar in standard tuning is about 42Hz, and the lowest note on
a Bösendorfer concert grand piano is 27.5Hz. (By the way, I’ve heard that RBH makes
excellent subwoofers.)
Speakers are difficult
Every loudspeaker design involves compromises, but the RBH
MC-6CT had many virtues and few vices, and its set of strengths makes it a strong
contender at its $999/pair price. It was quick, clean, articulate, and fun to listen to,
unfussy about placement, and well finished. It didn’t take megawatts to get going,
and remained articulate at lower listening levels. Its sins were more of omission than
commission, and should be largely ameliorated with the right choice of partnering
equipment. It did some things better than my Magnepan MG1.6/QRs, and some things about as
well, punching harder than my Maggies in the bass but lacking the panels’ bass bloom.
The RBH was satisfying to listen to with a wide variety of music, and should be revealing
enough to respond positively to system upgrades. Speakers may be difficult, but the RBH
MC-6CT is easy to recommend.
...Chris J. Izzo
Price of equipment reviewed
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