Rethm Maarga loudspeaker

Hi-fi is like cake. Most people enjoy listening to music, and most people like cake.

People who like cake tend to like different things about it. Some people like a flourless cake, some people like a fluffy angel food cake, and some like a cake loaded up with little pieces of carrot and God-knows-what-else. People who like hi-fi also tend to like different things. Some like punchy, forceful sounds, some like realistic, natural tones, some like texture and color, some like "air," and some like to hear things go whooshing from one speaker to the other. It's all okay.

If hi-fi is like cake, amplifier power is like sugar. It has its place. But when people thought it was abundant, cheap, and harmless, they went whole hog on it, minimizing and even throwing out other ingredients because, hey, sugar is cheap. And fun. And harmless.

But there exists an entire movement devoted to low-power amplifiers, the idea being: A low-power amp, with its lower parts count and simpler architecture, stands a chance of being faster, more nimble, and more transparent to the source—ie, more capable of getting out of the way of the music. And with that movement comes a complementary interest in loudspeakers of greater-than-average sensitivity and efficiency—a genre that, to some hobbyists, reaches its pinnacle with the full-range (or at least quasi-full-range) driver: crossoverless, fast, and typically sensitive, not to mention elegant.

A somewhat early participant in the modern (footnote 1) high-efficiency speaker movement—their first commercial speaker, which I wrote about in Listener (footnote 2), debuted in 2000—was Rethm, whose products are manufactured in India. At that time and for more than a decade after, all Rethm loudspeakers had two predominant characteristics: They were designed and built around Lowther full-range drivers—high-sensitivity things with lightweight paper cones, powerful magnets, and almost unimaginably small voice-coil gaps—and those drivers were loaded with enclosures made from segments of fiberglass pipes.

The pipes remain, but the Lowther drivers have been replaced by full-range, Lowther-like units designed and made by Rethm: lightweight twin-cone paper diaphragms, pliant foam-rubber surrounds, neodymium magnets, the works. Those characteristics and a good many more are embodied in the recently redesigned Rethm Maarga ($10,750/pair)—the third distinct version of this midline product.

The new Maarga—the name means "the path" in Sanskrit, especially as it applies to the path followed by an Indian classical musician as he or she makes the journey from beginner to virtuoso—stands 41.2" tall and measures 22" deep and a scant 7.5" wide. Included with each Maarga are four auxiliary feet, which add slightly to its height; each foot comprises an upper and lower metal disc, both 2" in diameter, with three ball bearings between them. (Dimples are machined into the "mating" surfaces of both discs, to keep the balls in place and allow them to do their vibration-isolating thing, à la Symposium Acoustics' Rollerblocks and similar accessories.)


The Maarga's full-range driver is 6" in diameter, with a parchment-like paper cone and a 2.5" "whizzer" cone of the same material, the latter for propagating higher frequencies. At the center of the whizzer cone, which bears a ring of six evenly spaced perforations, is a vaguely spade-shaped (as in "ace of") metal phase plug. The driver's mounting rim is obscured by a trim ring, made with a great many perforations of its own, said by designer Jacob George to help ameliorate high-frequency diffraction effects.

The structure to which that driver is fastened comprises three sections of fiberglass pipe, all with an outside dimension of 7.25". These are cemented together to form an inverted U, which appears to have a total length of 80", give or take—but this isn't a simple case of throat (driver) at one end and mouth (listening aperture) at the other. Rather, the driver is fastened to the front of the upper transverse pipe, which in turn leads to the rear descending pipe, which is open at the bottom—yet, directly below the driver, there is also a front descending pipe, also open at the bottom (although a close look reveals that one half of the tube is occluded just above that opening). Sandwiching the U are a pair of nice-looking side panels, the outer surfaces of which can be ordered with wood veneer or black acrylic. My review loaners bore the latter.

Rethm describes the Maarga's enclosure as a horn-loaded labyrinth. Traditionally, such a thing would require a gradual increase in its cross-section, from throat to mouth, in order to achieve the acoustical impedance transformation required for a true horn effect—yet there's no outward evidence of such in the Maarga's enclosure. It seems possible that a horn effect is achieved via structures concealed within the fiberglass pipes, but I would also guess that the Maarga's enclosure functions as a quarter-wave pipe. For the record, 80" correlates with a quarter wave at 42Hz, which is within spitting distance of the low E string of a bass guitar. Just sayin'.


One thing that's not in question: The Maarga's bass frequencies are handled by two 6" × 9" woofers, driven by a well-hidden internal amplifier and loaded isobarically, with only one woofer firing into the room and the other mounted directly behind it, firing into a sealed chamber. Both drivers get the same signal from the user's amplifier, but the innermost driver isn't meant to be heard: Its effect is to create for the outermost driver a loading chamber of variable pressure. During rarefaction, the front driver's cone excursions are accompanied by the same in the rear driver, which serves to trick the audible driver into working as though it were loaded by a much greater volume, thus allowing it to behave as it would in free air, but without dipole cancellation. (Here, the restorative characteristics of the drivers' elastic surrounds and spiders are not dispensed with but rather fortified, electrically; isobaric loading is, in a sense, Acoustic Suspension with brains—which is to say, Acoustic Suspension with greater and more consistent control over the woofer's operating conditions and with less susceptibility to changes in compliance as the driver suspension ages.)

The internal amplifier that drives those two woofers is based on a Hypex class-D module and is specified as providing 400W. At the bottom of the rear descending pipe is a curved panel that includes a pair of banana sockets for connection to the user's amplifier and an IEC socket for the amplifier's AC cord, plus four small control knobs: an on/off switch; a ground-lift switch; a bass level control that goes from Lo to Hi; and a crossover frequency control that goes from 60 to 240 (Hz) with a detent at 120.

Installation and setup
No owner's manual is supplied with the Maarga, and there appear to be no downloads available for such on the Rethm website. That being said, unpacking—and consequent repacking—were intuitively easy, aided by a well-designed carton that seems capable of surviving multiple trips: a reviewer's boon. Also boony was the assistance I received from Mark Sossa of Well Pleased AV, the company that distributes Rethm in the US, who visited my home in Albany, NY, to help with installation and setup.


On that topic, I have nothing remarkable to report. Apart from the above-mentioned rollerfeet, no assembly was required, so installation was a simple matter of unpacking the speakers (doable by one person, although a second pair of hands made light work of it), walking them into place, installing their feet, connecting their AC cords, and connecting my speaker cables to the Maarga's banana sockets (spade connectors cannot be accommodated). Sossa aimed the enclosures straight ahead, with zero toe-in, and placed the two speakers slightly closer to one another than my reference Altec Flamencos; they wound up 68" apart, measured on-center, with their back surfaces approximately 39" from the front wall. Amplifiers included my Shindo Haut-Brion (push-pull, 20Wpc), a Shindo Cortese (single-ended, 10Wpc), and the Air Tight ATM-300R (single-ended, 9Wpc). According to an email from Jacob George, my review samples had been used for about 60 hours before being shipped to my house.

Once in my system, the Maargas brought to it a combination of strengths and weaknesses very different from those of my Altec Flamencos and DeVore O/93s. The Rethms were "airier" and more open than either, with spatial performance that was also superior (especially relative to the Altecs): Images of instruments and voices were more distinct from one another than I usually hear at home, some addressing me from a stage of greater-than-average apparent depth. On the down side, my system's sense of scale took a step backward—the size of everything was now medium-small to medium—and there was a lack of midrange richness. There was also a bit more upper-mid graininess than I'm used to hearing.

Footnote 1: The distinction is important: Early in the history of the audio industry, high efficiency was regarded as an indicator of good engineering—correctly, I think.

Footnote 2: I wrote about the Third Rethm in the May 2003 Stereophile and the Rethm Saadhana in our April 2008 issue.

Rethm/Design Build PVT Ltd.
US distributor: Well Pleased AV
1934 Old Gallows Rd. #350-R
Tysons Corner, VA 22182
(703) 750-5461

Bogolu Haranath's picture

Wilson Sasha DAW frequency response is somewhat similar to the Rethm Maarga ......... See, manufacturer's comment ..... Sasha DAW also has a 'dip' in the presence region in addition to midrange 'dip' :-) ........

Bogolu Haranath's picture

DeVore Gibbon X also has similar FR as the Rethm Maarga, with additional 'dip' in the presence region :-) ......

JHL's picture

...they all have round drivers too!

Bogolu Haranath's picture

and ..... they all need amplifiers to drive them too! :-) ........

Bogolu Haranath's picture

and ....... they all need speaker wires to connect them to the amplifiers! :-) ........

Bogolu Haranath's picture

Rethm Maaga is a little bit different though ....... It has a 'whizzer cone' :-) ........

acresverde's picture

So is the full ranger 6" as stated in the "description" or 8" as stated in the "specification"?

Sea Otter's picture

"I found several high-Q modes in the midrange on all the surfaces (fig.2). Given the Maarga's very high sensitivity, this behavior is unlikely to be audible."- JA

I am curious as to JA's reasoning behind this statement. Sensitivity is an electrical parameter, or how much electrical input is required to get a specific acoustic output.

I do not understand why the sensitivity of the loudspeaker. Would have anything to do with the excitation of resonnant modes in the enclosure. The sidewalls of the speaker should be effectively "blind" to the electrical input, only responding to the mechanical and acoustical output of the speaker cone. As most investigations have shown that it is primarily the acoustic pressure transmitted through the air inside the enclosure, which excite midrange modes, even the fact that the cone may be slightly lower in mass should have little impact.

Would you help me understand your reasoning behind your statement?

John Atkinson's picture
Sea Otter wrote:
John Atkinson wrote:
I found several high-Q modes in the midrange on all the surfaces (fig.2). Given the Maarga's very high sensitivity, this behavior is unlikely to be audible."

I am curious as to JA's reasoning behind this statement.

I measure a loudspeaker enclosure's vibrational behavior with a standard input voltage. This means that the higher the speaker's sensitivity, the greater the output of the drive-units compared with that of the enclosure.

John Atkinson
Technical Editor, Stereophile