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MMR Thummim Review – Abstraction

Pros – 

Tough, ultra-premium build and design, Eletech Plato included, Robust yet highly discerning bass, Clean and refined top-end, Cavernous soundstage

Cons – 

Not for those wanting a neutral sound, Midrange timbre isn’t especially accurate, Not as sparkly as some flagships, Somewhat awkward ergonomics

Verdict –

The Thummim is for the discerning listener wanting a thoroughly engaging and enveloping sound with a design and unboxing experience akin to a modern art piece.

Introduction –

Metal Magic Research (MMR) is a new audio company spearheaded by Joseph, the man behind the formidable Jomo Audio. Their main focus is on the adoption of the latest technologies alongside artisan metal universal designs. MMR takes heavy inspiration from Alchemy with their earphones, which all tell a story of sorts with their naming and design. After reviewing the MMR Homunculus, I was excited to try their flagship hybrid, the Thummim which serves as a showcase of what the company can achieve if cost is no object. The Thummim almost ushers in a new age of hyper-exclusive portable audio, with almost unprecedented pricing. And, despite this, MMR ensures the buyer feels rewarded by their decision to the best of their ability. I was relieved to see that even their most outrageous design is underpinned by a quality sonic foundation.

The Thummim is available on MMR’s website at a recommended price of $4499 USD. You can read all about it and treat yourself to one here.


Disclaimer – 

I would like to thank Joseph from MMR very much for his quick communication and for providing me with the Thummim for photographing and review. All words are my own and there is no monetary incentive for a positive review. The earphones are to be returned to Joseph and I will attempt to be as objective as possible in my evaluation.


Specifications – 

  • 9 Triple Hybrid Drivers Configuration
  • Quad Electrostatics, 2 Vented Mid, 2 Highs, 1x Bespoke 9.7mm Foster Dynamic Driver
  • 4-Way Passive Electro Frequency Division
  • TriBore Waveguide
  • Eletech Proprietary Internal Litz
  • Frequency Response: 20Hz-80kHz
  • Impedance: 35ohm
  • Noise Isolation: -18db (UIEM)


The Pitch –

Tribrid Design

The Thummim implements a whopping 9 drivers in a highly sophisticated 4-Way design. Covering the bass is a Foster dynamic driver, a subsidiary of Fostex Japan who are very prominent in the high-end headphone world but have more recently branched into IEMs. Meanwhile, 2x Knowles BA drivers cover the midrange and another pair the highs. A quad 2nd generation Sonions electrostatic tweeter array acts as a super tweeter in conjunction with a horn-like nozzle.

3D Printed Acoustics

In a similar fashion to Campfire Audio’s Solid Body design, the Thummim unites its 9-drivers with a 3D printed chassis with all waveguides printed in one piece. This improves the phase and accuracy of the sound while permitting MMR greater control over the frequency response too.

Eletech Wiring

MMR has once again teamed up with Eletech to add finishing touches to the Thummim in the shape of the pure silver Plato cable alongside internal Litz wiring. I subjectively find the clear and open sounding Plato a fine complement to the Thummim’s full and robust tuning. This cable also provides excellent ergonomics and feels like a high-quality component built to last.


Unboxing –


Special mention must go to the packaging which secures the exclusive and premium status of the product. The round box contains a magnetic leather case with a 3D printed skeleton that secures the earphones and accessories in an organised fashion while also serving as a fitting platform to showcase the Thummim’s titanium shells. The accessory set is, otherwise, quite similar to the Homunculus with an array of premium Japanese Acoustune ear tips alongside an Eletech custom cable. There is no portable carrying case which may have been a nice addition for those intending to take their audio on the go.


Design –

In the context of Campfire Audio IEMs becoming in some sense, mainstream, the Thummim actually comes across as a more “conventional” looking IEM when compared to its more discoid sibling. However, make no mistake, the very same unyielding impression of quality, density and rigidity remain here; and the Thummim makes a resounding visual statement. The full titanium shells are well-weighted and superbly finished with very even faceplate matching and no blemishes or flaws. The triangular faceplate ornament serves as strong visual contrast to the angular housings making them a delight to the eye.


The cable doesn’t fail to impress either and extra thought has been given to the 0.78mm 2-pin connectors that use a spring-loaded mechanism as opposed to static tension. This promises a longer lifetime and sustained performance with many plug/pull cycles. We observe a higher-end cable than the Homunculus as well, a variant of the Eletech Plato with custom y-split and plug that match the colour and finish of the Thummim’s shell. This pure silver cable is flagship level with a finish and feel to match. It’s immediately very ergonomic; soft and pliable with minimal memory and microphonic noise transmission. The ear-guides are pre-moulded and very well-shaped providing a comfortable fit. The experience here, is once again, immaculate and distinct.


Fit and Isolation –

From eye-balling the shape of the housings, the Thummim appears more ergonomic than the Homunculus. However, in use, I actually found the Homunculus easier to fit. In particular, the Thummim is quite a large earphone, both in terms of depth and length so it presses against the tragus and anti-tragus of my ear. As the housings are quite angular, this did cause some discomfort, requiring a break after every hour of listening. Unfortunately, due to the angle of the nozzle, I was unable to angle the housings upwards to place the bulk outside of my ear.


Smaller eared listeners will likely not have a great experience here. Isolation, on the other hand, is quite good for a hybrid. Surely, it is not comparable to a CIEM or fully-sealed BA earphone, but the experience is good here and easily suitable for commute and public transport. They don’t pick up too much wind noise despite their wider design either which does aid with outdoor listening. Despite being heavy and the fit a bit more temperamental than most, they were stable in my ears during daily use.


Sound –

MMR Thummim

Testing Methodology: Measured using Arta via IEC 711 coupler to Startech external sound card. 7-9KHz peaks may be artefacts/emphasized due to my measurement setup, less so with deep fit. Measurements besides channel balance are volume matched at 1KHz. Fit depth normalized to my best abilities to reduce coupler resonance. Still, due to these factors, my measurements may not accurately reflect the earphone or measurements taken by others.


Preambles –

Let’s address the question on everyone’s mind. What does a $4500 earphone sound like? I was a bit wary of this as it is, first and foremost, a boutique item. That means a statement product and usually not something designed for mass appeal. The Homunculus is also not an earphone that I found especially conventional. However, after just a few moments with one of the world’s most expensive earphones in my ears, the experience was… quite normal. This is admirable on MMR’s behalf, demonstrating that they haven’t shot for novelty, leveraging that some listeners may misconstrue different as better. No, this is an appealing tuning that many will enjoy; highly engaging and a strong showcase for very high acoustic quality.


Tonality –

The Thummim is a W-shaped earphone, surely on the musical and engaging side. It features a robust sub-bass response followed by a full but not excessively warm mid-bass. The midrange tuning is slightly more unorthodox and upper-midrange biased to some extent. However, it appears well counterbalanced by the fuller bass alongside a centre midrange bump that introduces a strong vocal presence and size. The top-end is crisp and detail dense with pleasing instrument body. What brings it together is the spheroid soundstage which makes it a thoroughly immersive listen.


Bass –

Coming from the very natural and balanced Homunculus, the dynamic, impactful and engaging tuning of the Thummim was surely a surprise. Like that model, the Thummim features a DD by Foster and once again, I am very impressed by the quality on offer. The Thummim, however, introduces a substantially bolder bass, with a weightier and harder-hitting sub-bass followed by gradually declining emphasis into a recessed lower-midrange. The result is full and robust bass notes with a touch of warmth and just a hint of mid-bass tubbiness, but otherwise, impressive cleanliness and excellent dynamics. The level of driver control on Foster’s models, also MMR’s implementation of such, continues to be a highlight.

This is a markedly more aggressive presentation than the Homunculus with a heavier impact but similarly, a modest, natural decay. So though enlarged, notes remain highly defined and organised, with good separation and excellent detail retrieval in the sub-bass especially without sacrificing texture. Boot up a pacey song like Hey by the Pixies and bass drums attack with lucid clarity while digging deep with a guttural quality. Impressively, this is never to the detriment of slower tracks that are devoid of drone or dullness; think Radiohead’s No Surprises. The Thummim isn’t a perfectly linear earphone here, but a highly engaging and textured performer that exemplifies the best qualities of a DD driver with its technical mastery.


Mids –

The tuning of the midrange is perhaps most unorthodox and roughly reminiscent of the direction Campfire Audio have taken with their latest earphones. We can observe 2.5kHz and 4kHz peaks alongside a noticeable 3kHz trough. This inverts common reference curves yet, despite this, the presentation sounds relatively normal; only a little more track sensitive than earphones more closely following the Harman or Diffuse-Field neutral curves. There’s good bass/midrange separation instigated by a mildly recessed lower-midrange. However, as bass is quite full, vocals aren’t too thinned out nor strained. Rather, they are presented with a lush and full-bodied character. Vocals come across as a touch laid-back in positioning likely due to the 3k tuning. However, remain mostly in balance with instruments due to the recessed lower-midrange.

The centre-midrange bump reinforces this, by bolstering vocal size and, accordingly, there also isn’t too much warmth which retains high definition. A prominent upper-midrange bump further contributes to vocals clarity and definition, counterbalancing the Thummim’s added fullness. Vocal extension is, in turn, excellent though at times, vocals do come across as raspy albeit not sharp or strained. Despite also featuring a slightly forward lower-treble, I do not hear notable sibilance but they can sound over-articulated on certain tracks. I can only attribute this to the 3K tuning which appears to be contributing to a more robust albeit less forward vocal presentation. The more an earphone deviates, the more difficult it becomes to articulate what I’m hearing. Despite all of this, the voicing is natural, never strained, chesty or veiled. The Thummim is full and powerful yet also clear and defined at the cost of being a touch more laid-back.


Highs –

With the Homunculus I was very impressed by its rather linear and neutrally positioned lower-treble which yielded an accurate instrument timbre and excellent detail retrieval. The quad-estat Thummim once again comes across as more technical but also more engaging here. The lower-treble sits a touch forward, not piercing but crisp and with copious detail presence. The transient response is immaculately clean as good estat implementations often come across to me. However, similar to others, instrumentation is a touch thin with a light note weight. Sonion’s estat tweeters actually do not cover the lower-treble, and this was confirmed with Joseph as well, but they do influence the instrument timbre to my ear. I think especially notable about the Thummim is its background, which is dark and super clean. This isn’t the energetic and sparkly presentation one might be accustomed to on a pure BA setup, but a much smoother and more refined albeit also laid-back presentation of micro-detail and air.

The Thummim has great headroom, nonetheless, and conveys a very convincing sense of distance. It has great foreground/background contrast which contributes to a well-layered and, in turn, well-organised presentation. This enables the earphone to achieve a rather effortless detail presentation even when the track becomes busy with high separation and quick transients. Resolution is very high too, even if the highest octaves aren’t especially bright; there is a clear, low-distortion extension to the very top. The Thummim gives you the foreground detail presence to engage and gratify with an immaculate background and effortless micro-detail presentation that enthral over long critical listening sessions. It is another earphone that excels with long-term listenability with its complete lack of brightness and glare while introducing a bit more engagement to ensure this isn’t ever mistaken for a detail-deficient sound.


Soundstage –

Many listeners would consider a wide soundstage to be a defining trait of a high-end IEM. However, the Thummim’s forte is without a doubt depth, achieved via a grand, expansive bass alongside a slightly more laid-back vocal image. Width stretches well beyond the head when called for, however, the depth seems to project most exceptionally, stealing the show. Indeed, the presentation is quite spheroid as quoted by MMR themselves. The result is an open, almost cavernous soundstage presentation that provides a convincing sense of immersion and atmosphere. Imaging is enjoyable too, not perfectly linear and balanced but with sharp directional cues and a very clean transient response. The W-shaped tuning retains high tri-frequency separation alongside strong technical ability throughout which permits defined and easily isolated notes. The Thummim is tuned in such a fashion that small details almost stand out so it is not technically the most accurate but certainly tuned for great musical enjoyment.


Comparisons –


MMR Homunculus ($1699): MMR’s cheaper model appears less dynamic and grand at a glance but presents a more natural sound when not in direct reference to the Thummim. Its bass is more linear and natural with a more balanced presentation. The Thummim has much more presence, especially sub-bass, making it bolder and harder hitting. The Thummim also has more aggressive note attack while the Homunculus presents a smoother textured note. Within the midrange, the Homunculus is more vocal forward, they are similarly enlarged but more linear with a more accurate timbre to my ears. Meanwhile, the Thummim is more engaging, it has greater clarity and contrast, sounding wetter yet also fuller at the expense of presence. So though the Homunculus is technically a bit more accurate, I can see why many still prefer the Thummim.

The top-end tells a similar story, the Thummim being crisper, more aggressively detailed and providing a sizeable step up in headroom and extension. The Homunculus is more natural while the Thummim is more detailed with greater air and especially resolution. The Thummim has a larger stage in all dimensions and is more spherical in shape. Its has more defined layers and sharper directional cues. It also has more exaggerated separation while the Homunculus actually has a bit more separation within each frequency band due to its more mellow tuning. Overall, the Thummim is more technically adept but is also tuned to showcase its strengths which exaggerates the difference in performance. If you’re looking for a more natural presentation, the Homunculus fits the bill nicely. Meanwhile, the Thummim executes a grander and more engaging sound with aplomb.

Campfire Audio Solaris 2020 ($1499): The Solaris 2020 is a fine successor, appending many faults of its predecessor and representing CFA’s best efforts at a hybrid. Unlike MMR here, the Solaris 2020 is aiming more for mass appeal, and it is priced in a more attainable manner. The bass is slightly more present on the Thummim, it has more weight in the sub-bass but a similar voicing overall. The Thummim has thicker, bolder notes and is harder hitting at the very bottom. The Solaris 2020 is slightly more natural in its expression though the Thummim is more textured and defined while the Solaris 2020 is a bit more balanced. Vocals are more forward on the Solaris 2020 yet both are enlarged to a similar extent. The Thummim is more full-bodied and a touch warmer while the Solaris 2020 is thinner and a bit cleaner tonally. The Solaris 2020 has better definition and greater clarity while the Thummim has a richer and more powerful voicing.

The Thummim sounds a bit wetter as well, having greater vocal extension and a touch more openness to female vocals despite being fuller otherwise. The top-end presentation is quite different too. The Solaris 2020 has a slightly more aggressive lower-treble and it has more focus here while the Thummim is a bit “floatier” due to the lighter note weight instigated by its estat super-tweeters. The Solaris 2020 also has more sparkle and energy while the Thummim has a cleaner transient response with more pure resolving power and separation alongside a cleaner background. The soundstage presentation is wider on the Solaris 2020 but deeper and taller on the Thummim. Its imaging is actually a bit more holographic and layered than even the Solaris 2020.

Empire Ears Wraith ($3499): The Wraith features an 11-driver setup with 7-BA drivers and similarly, Sonion’s 2nd generation quad estat super-tweeters. However, the implementation and approach is very different. The bass is not as dynamic nor as deep-reaching although impressively so for a BA earphone. The Thummim is bassier and more dynamic. The Wraith decays quicker and has a more natural note presentation, it’s also a touch more defined as a result. Meanwhile, the Thummim is more engaging and aggressive. The midrange presentation also provides quite striking contrast. Where the Thummim is robust yet clear and open, the Wraith is enlarged and vocal forward but dense and smooth. So essentially, they are similar when taken at face value but take opposing approaches. As such, the Thummim sounds more extended and open while the Wraith sounds a bit more truncated but also more smoothly articulated.

Its vocals are denser, more whole and more fully-resolved but also more truncated in terms of voicing. It doesn’t have quite the same low-end bolstering so it remains a clear and defined performer with good separation. Accordingly, the top-end is smoother too on the Wraith. The Thummim is crisper and more detail forward, achieving subjectively, better balance. The Wraith is very detailed too and epitomises that lush, smooth and refined sense of micro-detail delivery but without the aggressive foreground. As such, it has less contrast but, similar detail retrieval overall nonetheless and, in a sense, the background details are more apparent because the foreground is not so present. The Wraith presents a wider soundstage while the Thummim achieves more depth. The Wraith has a more layered midrange while the Thummim has sharper directional cues and a more holographic top-end.


Verdict –


The Thummim remains a piece of sonic excellence, and never once sacrifices quality in its pursuit of exclusivity – as one might experience from other boutique-brand products. Certainly, we are heavily within the realms of diminishing returns and, in turn, you are still paying dearly for a sense of exclusivity and innovation. Though it will never serve as a reference earphone in a professional setting nor provide ideal ergonomics, I found my hands gravitating towards them every time I sat down for a listen. For, much like the design, the sound too achieves a level of abstraction and I mean that in a positive sense – a freedom in representation. These are tuned first and foremost for musical enjoyment with a rich, superbly textured bass alongside a full-bodied yet well-defined vocal range. The top-end, though not the most overtly resolving at a glance, remains highly detailed under scrutiny and delivers that detail in a refined and immaculately clean manner. The Thummim obviously is not an earphone with mass appeal though its sound I feel will be easily likeable by many. It is a product for the discerning listener wanting a thoroughly engaging and enveloping sound with a design and unboxing experience akin to a modern art piece.

The Thummim is available from Metal Magic Research (International) for $4499 USD at the time of writing. I am not affiliated with MMR and receive no earnings from purchases through this link.


Track List – 

Arcade Fire – Everything Now

Blue – 13

Courtney Barnett – Tell Me How You Really Feel

Dirty Loops – Loopified

Girl’s Day – Girl’s Day Everyday No.5

Kanye West – My Beautiful Dark Twisted Fantasy

Kehlani – Honey

Mac DeMarco – This Old Dog

MAMAMOO – reality in BLACK

Missy Higgins – Sound Of White

NIKI – Zephyr

Nirvana – Nevermind

Pixies – Doolittle

Radiohead – OK Computer

Rich Brian – Love In My Pocket

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