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Rethm 2nd loudspeakers
by Constantine Soo
September 16, 2004
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Specifications:
Type: Lowther-based, floor standing, full-range speaker
Driver: Lowther DX-4
Frequency Response: 45 Hz – 22k Hz
Sensitivity: 99db/8 Ohms
Dimensions: 1056 (H) x 900 (D) x 320 (W)(mm)
Weight: 88 lbs
MSRP: $6,480 per pair
Contact:
Vector Transworld Corporation
444 South Flower Street, Suite 1688
Los Angeles, CA 90071
Tel: (213) 624-4704 Fax: (213) 624-1188
Email (for general inquiries): info@rethm.com
South Asian Office
Design Combine
Kusumagiri P.O., Kakkanad
Cochin 682030, India
Tel: +91-484-2421731, 2421732 Fax: +91-484-2317211
Email: jacob@rethm.com
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BACKGROUND
Some dynamic loudspeaker manufacturers consider the preservation of a
music signal’s spectral coherency their top design priority, and often favors
the 2-way approach. Although many manufacturers offer more than just the 2-
way designs and companies producing strictly 2-way speakers are few,
oftentimes these companies’ best efforts are their 2-way designs.
Then, there are those dynamic speaker makers that elect to pursue an even
more purist venue in the form of crossover-less single-driver designs. Rethm
of India is among the devout group of loudspeaker manufacturers that
believes in the sonic realism such design will transpire even when compared
to the best of the tweeter/woofer 2-way designs.
To Jacob George, Rethm’s proprietor, drivers developed from the latest
technologies for reenacting credible engine roars and planetary annihilations
have no business taking part in the consecrated music reproduction
environment, and spectral coherency is just as important to him as tonal purity
and single cone dispersions. At the end, expeditious transients and single-
cone radiation are the absolutes in Mr. George’s mind for attaining natural
dynamics and tonal coherency. To achieve his goals, Mr. George adopts
Lowther’s 8-inch, neodymium magnet, paper cone DX4 driver.
Jacob George has definitive but realistic expectations in marrying his Rethm
enclosure to the Lowther DX4, and in modifying the Lowther driver to his own
specifications. The DX4’s original paper cone is proliferated by two inner
layers of Rethm‘s own perforated paper cones, which in turn encircle a
sizable, central wooden phase plug of Rethm’s design. The outer Rethm cone
is attached to the driver’s diaphragm, while the inner perforated cone is
attached to the phase plug, providing certain inertia for curtailing certain
spectral anomalies. David Dicks of Lowther USA, in a 2-hour phone
conversation with me, acknowledged that the DX4 is the most detailed, full-
range Lowther driver ever designed for use in bass reflex enclosures.
The 2nd Rethm’s suggestive virtues are all readily visible. As Mr. George
intended his loudspeakers to be rid of cabinet reflections and resonance, the
molded plywood cabinet‘s front baffle is sculpted in a vertical cylinder
extending all the way to the floor. At the top of this cylinder is a shorter, open
cylinder flipped perpendicularly upward to house the Rethm-modified
Lowther. With such construct and visual effects, my wife considers the 2nd
Rethm the most visually appealing of all speakers in the house alongside the
lacquered Madrone Audio Note AN-E SEC Silver.
Inside the top enclosure, the rear center of the Rethm-modified Lowther DX4
driver is encased in a molded foam to absorb out of phase higher
frequencies. Lower frequencies emanating from the outer cone’s rear are
allowed to double-back pass the damping foam and down a labyrinth for bass
augmentation, diverting into two separate routes at a junction and eventually
exiting through a port on the side of each of the two circular openings, one
measuring 9.6 inches in diameter, and the other 11 inches.
A single-wiring terminal is located at the lower rear of each speaker,
employing an industrial-grade, long durability plastic called Derlin, which
accepts only 4-millimeter banana plugs and connects to the DX4 via a single
1-millimeter strand of bare copper wire. This practice of coupling a bare wire
to a plastic medium was boldly pioneered by Japan’s 47 Laboratory in its
4708 OTA Cable Kit, in which a center plastic plug clipped with a copper wire
is fitted through a matching plastic outer shell, wrapped in another wire of
opposite polarity. By not passing the signal through metals and soldered
joints in conventional terminals, designs from both Rethm and 47 Lab are said
to deliver the least contaminated sound.
POSITIONING AND SYSTEM COMPATIBILITY
Mr. George set up his 2nd Rethm’s in my 12x27x8 listening room by situating
them at a little over 7 feet apart phase plug to phase plug, 8 feet from the
Lowther cones to the couch, and 7 ½ feet from the cones to the walls behind.
Incidentally, Mr. George set up his speakers in a virtual equilibrium without
using a measuring tape, and the height of the DX4’s were perfectly parallel to
the ear at the listening position.
In my experimentation of positioning, I was able to induce the Rethm’s into
performing the most convincing vanishing act of speakers, projecting a
modest-width but most aerial and holographic soundstaging, by repositioning
the speakers down to 6 feet apart and nearly a foot closer to the listening
position.
Moving the speakers past that point towards the listening position diluted
soundstage definition and accentuated an upper and lower midrange
prominence, one that hovered around the upper range of electric guitar
playing, as well as in clarinets and flutes. Repositioning the Rethm’s further
against the front wall beyond Mr. George’s prescription only served to induce
considerable degrees of the midrange excitability repeatedly. This excitability
resurfaced when the speakers were toed-in as well.
Dispersion of the Rethm’s when faced straight out was extraordinarily wide,
rendering the king’s sweet spot less of an issue, and facilitated a more liberal
listening environment that encourages spousal participation. The Rethm-
modified Lowther driver’s closer proximity to the listening area also minimized
the room factor.
By my estimation, the 2nd Rethm had an in-room bottom-end response at
around 60 to 80Hz, which my Genesis VI’s trio of active subwoofers were able
to complement with their controller’s cutoff set to the lowest point of 70Hz.
Conversely, the Genesis’ subwoofers represented a bittersweet engagement
in consideration of the Rethm’s near-proximity, optimal placement to the
listening position.
Within each of the Genesis 8-inch’s confinement, the 3 drivers operated in
concordance to each other to deliver the most extended and fastest bottom-
end; but the 42” tall, 11” wide and 18” deep Genesis VI mini towers dominated
the center of the listening room alongside the 2nd Rethm’s in the optimal sonic
integration. The effect was equivalent to having your own listening room
shrunk considerably, which your wife would certainly object to. Most
adamantly, too.
Relocating the Genesis’ to over 2 feet behind and to the side of the Rethm’s,
in spots where they augment the Audio Note AN-E SEC Silver most
effectively, the Rethm/Genesis engagement only served to produce detached,
odd spectral spread. A minimal-profile subwoofer system comparable to the
Genesis VI’s trio of 8-inch’s in flexibility, transient speed and power would be
an ideal partner, although such a dream subwoofer system remains elusive in
the marketplace.
The 2nd Rethm exhibited a predominant affinity towards finer digital front end
and interconnects over other parts of the system.
Led by the 47 Laboratory 4704 PiTracer CD transport, Combak Corporation’
s re-priced $4,400 Harmonix Reimyo 20bitK2 DAC, the DAP-777, made the
Rethm’s more coherent than 47 Laboratory’s $7,100 4705-G Gemini
Progression DAC, conceding only to the dual-mono 47 Lab’s dynamic and
tonal contrasts. Then, Audio Note’s upgraded, $30k DAC 5 Special induced
the Rethm’s to produce most vivid tonalities and wildest dynamics, with the
most mesmerizing spatiality to boost. In conjunction with the DAC and
amplification, AN’s Sogon digital and interconnects were essential in
conveying advantages in equipment upstream.
On amplification, the Rethm’s were noisy at idling with most tube amplifiers,
including Combak’s $36k Harmonix Reimyo CAT-777 and PAT-777
amplification, and the $6k pair of volume control-equipped Audion Silver Night
Parallel Single-Ended monoblocks. Loth X’s $15k JI300 integrated 300B
amplifier was the one remarkable exception whose quietness was on the par
with Linn’s $9k Klimax Twin stereo power amplifier as driven by the Reference
Line Preeminence Two Signature passive preamp, as well as 47 Laboratory’s
$7,100 Gaincard S integrated.
Then, Audio Note’s $10k M5 preamplifier proved to be the quietest tube
preamplifier thus far, as its pairing with the Linn KT in driving the Rethm
produced faint idling noise that was audible only with 2 feet of the speakers.
In terms of sound, the Audion monoblocks were already capable of superlative
dynamics when driving either the AN-E SEC Silver or Churchill Wideband,
with a reserve that was apparently never called upon in driving the 100dB,
crossover-less Rethm. For perspective, while the Audions’ volume pots were
consistently at 20 to 30% of full volume when driving the Audio Note or the
Tannoy, they never had to go beyond one-tenth of its full volume when driving
the 2nd Rethm.
Next to the Harmonix Reimyo suite in tonal resolution, the Loth X JI300
surpassed all others in sheer musicality. Its Tokyo Ko-On broadcast-grade,
stepped volume was even quieter than the 47 Lab’s DACT24 in operations,
scoring a notable point with the crossover-less Lowther. Retrospectively, it
was the Gaincard S that complemented the dimensionality of the Rethm most
convincingly.
A big “little” surprise. I put Steve Deckert’s midget, $499, 5Wpc, volume
control-equipped Decware SE84C to the test, and found the deprived-looking
SET a transformed curiosity. The degree of dynamics and loudness the little
Decware was able to induce from the Rethm elevated the little amp’s level of
competence many times over. Steve was correct in his response to my
March, 2002 Decware SE84C Review, that the crossover-less Lowther would
be a better match for his little creation than my 104dB efficient, crossover-
laden Klipschorn back then.
Doubly enticing was the fact that the Decware was just as quiet as the Loth X
at idling. The SE84C remains a $499 item even to this day, so every tube
aficionado could afford one. The suggestion of four Rethm’s and four SE84C’
s in a home theatre system accelerates heartbeat.
Despite its noted, varying behaviors towards front ends and amplifications,
the 2nd Rethm showed a curious insusceptibility towards the link between
amplifiers and itself.
Experimentation with my cache of copper and silver speaker cables did not
produce the differences in magnitude as did DACs. For instance, replacing
my reference Audio Note SPx silver speaker cable with the company’s own
large crystal copper AN-La rendered noticeable changes, but did not impact
the Rethms’ tonality to the degree that would disqualify the copper AN,
differing primarily in an improved top-end clarity in the SPx. Substituting the
copper AN-La with the Tara Labs Phase II w/TFA Return yielded a similarly
marginal inferiority, although in this case the advantage of the SPx became
more obvious.
In the aforementioned phone conversation with Lowther Speaker USA, David
Dicks further commented that because the DX4 was the most detailed
Lowther driver ever, he normally would recommend the DX3 or DX2 in most
cases, reserving the DX4 for customers with unusually absorptive, sonically
dull rooms.
The dilemma of a speaker being capable of giving too much detailing had
never happened to me, nor was I aware of speakers largely impervious to
differences between AN’s copper and silver speaker cables.
Among other things, the perfect speaker cable would sense the impedance
present at both of its ends proactively and calibrate its own property to
complement the relationship. In the absence of such wonder cable, I am of the
opinion that silver represents a superior medium for signal relay. Yet, the 2nd
Rethm seemed insensible towards the advantage.
This experience recalls an encounter of another loudspeaker with a similar
indifference at a dealership a few years ago, the owner of which tried to sell
me a renowned British monitor on the premise that I could save on amplifier
choices, as the 3 or 4 amps he rotated didn‘t make the speakers sound all
that different.
In light of the Rethm’s changes in its interaction with all things else, it appears
as if the Lowther harnesses a sensitive that lends less reliance on what comes
between an amplifier and itself, which would explain its relative indifference
towards advantages and characteristics silver cables have been effecting on
speakers I’ve reviewed, such as the Audio Note AN-E SEC Silver, Tannoy
Churchill Wideband, the Tannoy TD10, the ELAC CL330JET, etc.
MICRODYNAMICS AND DYNAMIC OUTPUT
Since the 2nd Rethm’s dynamic profile benefited from the rather nearfield
arrangement, which in turn enabled lower driver output in reaching higher
perceived volume in my listening room, the resultant level of detail from lower
midrange to the very top generated by the Rethm-modified 8-inch Lowther,
regardless of amplification being used, was among the most abundant,
approaching speakers in my household costing above $10k.
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