Reviewers' ChoiceRethm’s polymath founder, CEO, and designer, Jacob George, is based in Cochin, in southwest India. He brings to loudspeaker design a nontraditional vision informed by his love of wide-frequency-band, high-efficiency, single-driver speakers, vacuum tubes, his trainings as an architect and engineer, and a musician’s ear. His passions for audio and speaker design were driven by his pursuit of a type of sound reproduction that existed in his imagination: fast, coherent, highly detailed, yet nonfatiguing. The products of that pursuit have been steadily refined, and have culminated in the latest Rethm loudspeaker, the Maarga ($9750 USD per pair).

Maarga in detail

In the competition for the attention of audiophiles in a seemingly endless sea of rectilinear box speakers, the modernist lines and shapely curves of the Rethm Maarga catch the eye. My wife and my mother, neither of whom is known for her fondness for high-end audio components, murmured appreciatively during the Maargas’ pre-Christmas unboxing ceremony -- the first of several unusual listening experiences I had in the two months the speakers stayed with us.


Jacob George’s prototypes of his very first speaker were birthed in the early 2000s in Southern California, and were inspired by his being a music-loving artist and a relentless tinkerer. As he told me:

I was looking for a good, inexpensive speaker that could be powered by a low-power amp -- not valves (tubes), at that stage. My first amp was a headphone amp-preamp built by Steve McCormack, and he agreed to build me a custom power supply that took the power up to something like 5 watts per channel. I started researching and read about “high efficiency” speakers. Somebody suggested Lowther drivers as a good DIY option and that is where it all began. Got my first pair of Lowthers, put [them] into an enclosure I made with tubes in my friend’s garage, and despite a lot of frequency issues, its immediacy, “realness” and ability to “connect” blew my mind. I was hooked into wide-banders. Being an architect gave me the ability and the confidence to “problem solve” and resolve the design issues. I have always done product design as well, but of course here the added functional element of dealing with acoustics became a fundamental design criterion. Design is a “process” . . . and can be applied to anything. It is about resolving the functional and the aesthetic into one harmonious and seamless whole.

Over the past decade, George dropped the Lowther 5” wide-bander in favor of a custom-designed, 6” driver made in-house. According to him, it’s much smoother in frequency response, and lacks the Lowthers’ infamous peaks while retaining their high efficiency, dynamics, transparency, and immediacy. In addition to the full-range driver, the Maarga has a powered bass section -- two woofers housed internally in a sealed chamber, mounted in an isobaric configuration. George began with a custom-built, 75Wpc, class-AB amp and a passive filter, then moved to an active filter, then to a Chinese digital amp, and finally to a Hypex class-D amp rated at 400W. Late last year, he increased the size of the woofers “to get more punch and headroom in the bass. We went from a pair of 6”-diameter bass drivers to a 6” x 9” pair. This meant major changes as we had to redesign the enclosure, which ended up being 2” bigger in depth.”


I ended up being one of the first US listeners of the revised Maarga. It’s slim and deep, measuring 42”H x 7.5”W x 22”D. The bass unit forms a pedestal on which sits the enclosure housing the 6’ 8” labyrinthine horn. The pedestal is steadied by four easily adjustable outriggers. The metallic candy-flake enclosure has several finish options. Mine came in an attractive silver coat with beautiful side panels of sycamore.

The main, wide-band driver fires from the top of the enclosure. The downfiring woofers are hidden from sight in the base, with their volume and crossover controls (variable from 75Hz to 150Hz) on the rear of the base, along with the terminals. George believes that the shape of the cabinet is a critical design issue, and that a rounded cabinet sounds better than an angular one. Sensitivity is rated at 97dB/W/m at 1kHz, or “mean averaged from 200Hz to 2kHz.”

I am strictly a “form follows function” guy -- even with my architecture. So the whole premise of the design of Rethms, from the very beginning, has been driven by how the sound waves emanating from the driver [are] best delivered to the listener. And this has two parts to it. One is the external propagation of the waves and how it interacts with the exterior of the enclosure, and the other is the internal behavior of the sound waves. Starting with the former, waves reflect off the first surface it encounters. And when these reflections “beam” at the listener from a uniform flat surface, it will compromise the pristineness of the original signals being produced by the driver because the listener is going to be hearing multiple waves milliseconds apart. So what I did was minimize any flat surfaces on the front of the speaker and that is how the “signature” curved shells of the Rethms [were] born. You will also note that the bezel around the driver is the only flat surface, and even that has holes to break up the waves that hit it. Now the second part is what it does for the back wave of the driver -- which travels through the inside of the enclosure. Curved surfaces and volumes do not support standing waves. So the sound the listener gets at his seating position is extremely “clean.” The net effect is a complete lack of any “fuzz” and therefore great transparency and phenomenal soundstaging.

Given that I had several choices of amplifier to use with the Maargas, I asked George what he preferred. He responded, “I started with solid-state but, just like my first experience with wide-banders, I fell in love with valves (tubes) the very first time I heard one. I bought a very inexpensive EL34-based push-pull amp from Jolida, and the sound was an eye opener. SET’s were the culmination of that progression.”


I understand his preference for tube amplification. I, too, am a devotee, having fallen hard for a Shindo Laboratory Haut-Brion amplifier nine years ago, and three years later for a Shindo SET, the Cortese.

Test system

My listening was conducted with a Schiit Audio Yggdrasil DAC with the Analog 2 upgrade, an Innuos Zenith Mk.II Std. music server streaming Tidal and using Roon and an Apple iPad interface; a Garrard 301 turntable with Hana SL low-output moving-coil cartridge, Bob’s Devices Sky 30 phono step-up transformer, and Bob’s vintage-style phono cables; Shindo Laboratory’s Haut-Brion and Cortese power amplifiers and Monbrison preamplifier; Auditorium 23 and Skogrand Ravel interconnects and speaker cables; and power conditioning by a Shindo Mr. T. The only tweak I used was an Acoustic Revive RR-888 ultra-low-frequency pulse generator.

Behind the Rethm philosophy

I’m a practicing psychiatrist with more-than-passing interests in music and neuroscience, and my conversations with Jacob George revealed that his intuitions about listening to music align with my own, and are consistent with an explanation of brain activity found in Daniel Kahneman’s wonderful book Thinking, Fast and Slow. According to Kahneman, the brain processes information with two systems that operate simultaneously. System 1 works automatically, with little conscious effort or voluntary control. System 2 involves effort, concentration, and conscious choice. From this I extrapolate that if you find yourself thinking that a stereo sounds too “analytical,” chances are that it requires too much System 2 brain activity and not enough System 1: Cognitive strain mobilizes System 2. Stereos that put your mind at ease are likely stimulating more System 1 activity. System 2 involves your frontal lobe, the area of the brain devoted to attention and focus, while System 1 likely involves deeper limbic-system activity. Stereos that put your mind at ease are more likely to produce positive emotions, which is why most of us listen to music in the first place.

Gottfried Wilhelm Leibniz (1646-1716), a German mathematician who was one of the inventors of calculus, said that “Music is the pleasure the human mind experiences from counting without being aware that it is counting.” Contained in this observation is the idea that the pleasure of listening to a coherent, ordered series of sounds and harmonies is the pleasure the brain takes in engaging in an unconscious mathematical exercise. The precise reproduction of timing cues by highly resolving stereo systems reproducing performances of great music presents the brain with an exercise in parsing the mathematical relationships among rhythm, melody, and harmony, and that act of parsing gives the brain great pleasure because of this natural function of the mind. When the brain performs these pleasurable calculations effortlessly, they are by definition nonfatiguing and so tend to maximize pleasure, relaxation, and reward. Therefore, the best kind of speaker to come home to, to soothe our inner savage beasts, would be one that strikes a balance between resolution and the effort required to process that resolution. A single wideband driver per channel is an elegant way to achieve this psychoacoustic balance. A speaker with a single wide-band driver placed at the height of the listener’s ears is bound to be easier to listen to than a speaker with multiple drivers, each at a different height and each made of different materials, and requiring crossovers active in the midband, where most musical information occurs. George’s position is that the multiple wavefronts emitted by multi-driver speakers produce distorted harmonics and out-of-phase spatial information, as well as the potential for the smearing of low-level musical information. Phase accuracy theoretically leads to a more realistic, more informative, less fatiguing sound.

How did it sound?

Listening impressions

Juilliard-trained alto saxophonist Braxton Cook blurs the lines between musical styles while retaining elements of the traditional jazz he was educated in. His latest release, the fittingly titled Somewhere in Between (16-bit/44.1kHz, Fresh Selects/Tidal), is a startlingly fresh mashup of rock, jazz, R&B, funk, and electronica. With “You’re the One,” the Rethm Maarga strutted all its core strengths. A surging staccato synth line dropped me into a swirling vortex of sound. As Cook’s voice introduced the storyline -- he’s found his perfect love -- the Maarga masterfully choreographed and fleshed out the partners in the relationship: a fiery energetic electric lead guitar tamed by smooth, sultry sax counterpoint, until both dissolved into a soft percussion outro.

The Maarga’s uncanny ability to clarify the various musical lines and provide incredible detail for the sound of each instrument was also evident with “Hayati (My Life),” from Elwan, the latest from the Tuareg desert-warrior band Tinariwen (16/44.1 FLAC, Wedge SARL/Tidal). A single djembe pulled me in, then the fat bass groove, followed by an electric guitar as the singers begin a captivating call and response. It was remarkable to be provided with so much musical detail, and to be able to listen to it with no feeling of fatigue from information overload. Each instrument and voice was painted separately on the aural canvas, locked in to a specific area of the Rethms’ immense soundstage.


It was pure serendipity to stumble onto the music of virtuoso Shahnawaz Ahmed Khan. Acoustic guitar is an uncommon instrument for Hindustani classical music, but when I heard Khan’s bent notes, I thought it a match made in heaven. In “Placid Dreams,” from his Classical Guitar (16/44.1 FLAC, Worldwide/Tidal), Khan’s solo guitar lays out the outer borders of the melody in methodical fashion, marking the territory of the exotic scale, a swirl of ancillary fretboard squeaks providing just the right amounts of presence and detail. Halfway through, the tabla enters to provide rhythmic support to Khan’s soothing, soul-stirring guitar lines. The combination of the Maargas and my Shindo Cortese was especially luscious here, the amp’s single-ended-triode topology combining with the Rethms’ strengths to provide an ambrosia of natural harmonics. Acoustic instruments made of wood are a great test of any speaker’s realism because they create harmonics that are primarily even-ordered, and which tend to sound pleasing and soothing; odd-ordered harmonics tend to be more fatiguing.

The midband was in the Maargas’ wheelhouse, and women’s voices sounded special through them -- seductive, mellifluous, never bland or cloying. In “Imagining My Man,” from Aldous Harding’s Party (16/44.1 FLAC, 4AD/Tidal), the voice of this goth-folk New Zealander is unique and mesmerizing. The Rethms and SET amp beautifully combined to communicate the longing and disappointment in Harding’s tone and phrasing, but what was really stunning was the depth of the soundstage: Her sultry voice seemed to hover in midair, and when the smoky exhalations of Enrico Gabrielli’s tenor sax takes the melody, it was as if he’d stepped into the spot just vacated by the singer as they performed in some intimate venue. Similarly captivating was “If the Storms Never Came,” from Joan Shelley’s eponymous 2017 release (16/44.1 FLAC, No Quarter/Tidal), her voice gently suspended over the gentle throb of bass guitar and delicately fingerpicked acoustic and electric guitars.

Male voices, too, were compelling, whether Sampha’s lilting falsetto in “Plastic 100°C,” from his Process (16/44.1 FLAC, Young Turks/Tidal), or Matt Berlinger’s smoky baritone telling the story of “Humiliation,” from the National’s Trouble Will Find Me (LP, 4AD CAD3315). And the Rethms were masterful with “God Shall Wipe All Tears Away,” from Ladilikan (16/44.1 FLAC, World Circuit/Tidal), a brilliant collaboration by the Kronos Quartet and Trio da Kali, the latter a remarkable Malian ensemble comprising singer Hawa Kassé-Mady Diabaté, balaphonist Fodé Lassana Diabaté, and bass ngoni player Mamdou Kouyaté. Heaps of harmonic information are contained in the fascinating interplay of the West African instruments, the European strings, and the majestic and spine-chilling singing, and the Maargas’ attention to these overtones will leave those of you with any religious leanings feeling as if you’ve just had an extraordinary spiritual experience. And if that last sentence leaves you feeling left out, don’t worry -- you’ll feel the dopamine too; you’ll just interpret it differently.

Before hearing them, I was concerned that the Maargas would be hard-pressed to do justice to rock. I was wrong. The Rethms could indeed rock -- not with the usual in-your-face, concussive, frontal assault, but in a more subterranean, earthquake kinda way when I turned them up loud. The flabbergasting thing was when I used them to listen to rock at low volumes. It’s hard to imagine that a speaker could deliver utterly compelling rock at a level of only 60dB, but that’s exactly what the Maargas did, and like no other speaker I’d heard.

With “Endless Ways,” from Anathema’s The Optimist (16/44.1 FLAC, Kscope/Tidal), the Maargas did a remarkable job of preserving the weight and scale at low volume. The wideband drivers conveyed all the dramatic tension of the gradual buildup, and boatloads of microdetail and ambient cues, particularly in the bottom end, let me enjoy “Endless Ways” in the living room with my family as they read. That’s no small achievement.

I asked Jacob George to comment on this feature: “Yes, low-level listening is one of the Rethm’s side benefits, thanks to its high efficiency. The added advantage the Rethms have is that the bass can be adjusted. I am sure you have heard of the Fletcher-Munson curves that plot the sensitivity of the ear between the variables of frequency and loudness. At lower listening levels, you will have to compensate by turning the bass up.”

Indeed, I’d turned the woofers’ volume pots almost all the way up, and set the bass crossover to 120Hz. The woofers added enough drive to provide surprisingly compelling low-volume sound. This was also true with “Hula,” from the Icelandic band Sólstafir’s Berdreyminn (16/44.1 FLAC, Season of Mist/Tidal). There’s a brooding intensity as the music crescendos into a full-on Icelandic avalanche, and layered piano, brass, strings, and operatic background voices transport me into a frigid and beautiful Arctic winter. Think icebergs crashing under the Northern Lights, and Sigur Rós on steroids. The Rethm Maargas seamlessly articulated the rich, deep bass guitar and drums; the thick, realistic guitar and piano tones in the midrange; and all the nice, tinkly high-frequency bits. Loads of drama will leave you playing air baton with this one.

Cueing up “When the Levee Breaks,” from Led Zeppelin’s IV (LP, LDL65778), I looked forward to hearing how the Maargas would handle John Bonham’s devastating bass-drum groove, a great test of bass reproduction. They didn’t shirk the task. Although with rock I preferred the Shindo Haut-Brion’s swagger and crunch through the Rethms, Shindo’s Cortese 10W SET was no slouch, due to the Maargas’ remarkable efficiency. What was even more magical was the reproduction of the special effects in this track. The sound of the Maargas plus Shindo Cortese or Haut-Brion was unusually engaging, revealing nuances in a long-familiar recording I hadn’t expected to hear anything new from.


Vanessa Fernandez’s cover of “When the Levee Breaks” is the best track on her album of that title, a collection of covers of Led Zeppelin songs (16/ 44.1 FLAC, Groove Note/Tidal). Yes, naysayers and purists, it’s not Led Zep, but it’s a pretty rendition, and the Maargas did a remarkable job of re-creating the depth and space surrounding and between her voice, Luis Conte’s lively percussion, and Tim Pierce’s slide and acoustic guitars. Listening to Stanley Clarke’s revolutionary electric-bass technique in the title track of his classic School Days (16/44.1 FLAC, Epic/Tidal) was particularly illuminating -- not only were Clarke’s bass tones an incredible panorama of sound, but the Maargas were so revealing of his playing that I could visualize his virtuosity -- slaps, strokes, tickles, pulls, hammers -- as he coaxed unusual new sounds from his Alembic bass. The Rethms’ remarkable separation, lack of smearing, and imaging made each note easier to follow and “see.” And in Ray Gomez’s Strat-guitar lines I heard levels of sear, crunch, and bite that also served to correct my faulty presumptions about Rethms and rock.

I don’t often listen to large-scale orchestral music, but decided to play an LP given me by a client who’d found it at a Salvation Army store -- an unopened copy of Shostakovich’s Symphony No.13, “Babi Yar,” recorded in 1970 and performed by Eugene Ormandy and the Philadelphia Orchestra (LP, RCA Living Stereo LSC-3162). This ancient recording of Russian symphonic music proved a fascinating test of the Maarga’s virtues. Tom Krause’s rich baritone commanded my attention despite the language barrier, convincing me of the tragedy and injustice of the slaughter, by German soldiers and Ukrainian collaborators, of 33,771 Ukrainian Jews in January 1941, near Kiev. When I closed my eyes, I heard a wealth of spatial cues that produced an enormous soundstage: a convincing simulacrum of the concert hall.

I then cued up soprano Kathleen Battle and guitarist Christopher Parkening’s delightful collection of duets, Pleasures of Their Company (LP, EMI Angel DS-37351), which has a more intimate sound. With the Brazilian composition “Boi-Bumba,” the Maargas revealed a wonderful liquidity and purity of timbre in Battle’s voice that sounded just right, and continuously interesting. Moreover, the Rethm’s coherence, lack of phase artifacts, and production of true harmonics combined to give me the illusion that I’d just flipped a switch on a digital surround-sound processor and had been transported from a large concert hall to a small salon. This was also evident when I listened to something evidently recorded in a venue of more medium size: a performance by the chamber ensemble Lautten Compagney of Philip Glass’s The Windcatcher, Pt.1, and Melody for Saxophone No.12, from his Recent Recordings (16/44.1 FLAC, Sony Classical/Tidal). What I heard was haunting, deeply evocative, and true to life: the Maargas reproduced each instrument’s tonal richness, as well as its distinct positioning on the soundstage.


The Rethm Maarga is a unique speaker with little competition. Yes, there are other speakers based on wideband drivers, but none that I know of that offer its combination of high efficiency, low-frequency performance, and value. The Maarga is an extraordinary combination of sound and vision. I found it well suited to music lovers such as I -- those whose stereos are in the living room, not tucked away in a dedicated listening space. When they weren’t turned on, they were lovely pieces of furniture with high Wife Acceptance Factor. When they were turned on, they provided lively, enthralling sound that was immersive, real, and completely nonfatiguing. Given the Maarga’s fantastic sound quality at low volumes, it should also be well suited to the music lover who wants to listen late at night as the family sleeps. The Maarga might also be the ideal speaker for the music lover already smitten with low-powered amplification and/or tubes and who seeks a high-efficiency speaker at a moderate price (for the high end). The Maarga positively bloomed on that first watt, and needed no more than that to fill my living room with sublime sound.


That’s not to say that owners of high-powered solid-state amps couldn’t also fall in love with the Rethm Maarga, but such overkill would miss the point. If a big, beefy power amp is your thing, the Maarga’s allure will likely escape you. Think of a pair of mature, well-broken-in Maargas driven by a high-quality, cleverly designed, small-batch, low-watt amp as a long, complex, and magical marriage -- a wonderful, many-layered mystery tour to your favorite musical places. I found that the Maarga’s strengths -- microdetail, speed, soundstaging, coherence, layering, nuance, presence, depth -- came alive with just the tiniest bit of power. With a pair of Maargas wisely driven by such an amp, prepare to exit the audio-upgrade merry-go-round.

Maarga is Sanskrit for path; the word is often used in the context of seeking the path to enlightenment. Is the Rethm Maarga your path to audio nirvana? I’ve found it to be mine. A must-listen for the music lover with worthy amplification.

. . . Tom Mathew

Associated Equipment

  • Integrated amplifiers -- Luxman L-590AX, Spec RSA-F33EX
  • Power amplifiers -- Shindo Laboratory Cortese and Haut-Brion
  • Preamplifiers -- Bob’s Devices Sky 30 step-up transformer, Luxman EQ-500 phono preamplifier, Shindo Laboratory Monbrison preamplifier
  • Digital sources -- Aurender X100L music server, Innuos Zenith Mk.II music server and Zen mini, Luxman DA-06 DAC, MHDT Havana DAC, Schiit Audio Yggdrasil DAC
  • Analog sources -- Garrard 301 and 401 turntables on Chris Harban custom plinths
  • Cartridges -- Hana SL, Miyajima Shilabe and Zero mono, van den Hul Crimson Stradivarius
  • Speakers -- Horning Eufrodites Ellipse, Jamo R909, Vivid Audio Oval K1
  • Speaker cables -- Auditorium 23, High Fidelity CT-1 Enhanced, Skogrand Ravel
  • Interconnects -- Bob’s Devices Vintage phono, MG Planus 3, Sablon Panatela, Skogrand Ravel
  • Power conditioners -- Shindo Mr. T, Silver Circle Audio Tchaik 6
  • Ancillaries -- Symposium speaker stands, Kanso Audio Furniture, Acoustic Revive RR-888 low-frequency pulse generator

Rethm Maarga Loudspeakers
Price: $9750 USD per pair.
Warranty: Three years parts and labor.

Rethm Audio
Jacob George
Design Build Pvt. Ltd.
X/574-C, Kusumagiri P.O.
Cochin 682 030
Phone: +91 9349226365


US distributor:
Well Pleased Audio
Mark Sossa
Springfield, VA 22151
Phone: (703) 750-5461