MMR Homunculus Review – Empowered

Sound –

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.

Variances –

Though likely not the kind of press MMR would like to receive, a review should inform the reader. For those invested in this hobby likely would have seen some very critical impressions of the preproduction Homunculus when they initially debuted. Intentional or not, the woofer and tweeters in the demo Homunculus units at these shows were out of phase, greatly altering the signature and imaging characteristics. This has since been remedied with current batches and all retail units. As such, the unit being reviewed today and those that have been officially reviewed so far, will invariably sound very different to those sampled prior.

Tonality –

I hear a charming and relatively balanced sound from the Homunculus, impressively so for a hybrid, in addition, to undoubtedly a natural presentation. This remains a coloured one, however, so though carrying all the traits one would expect from a high-end IEM, it introduces a strong individual identity. In particular, I hear a slight bias towards vocals. Female vocals especially, are enlarged and forward, bolstered by increased density and empowered by a rich, organic tone. Such a voicing ensures the earphone never comes across as thin, strident or fatiguing, nor overly forward and intimate. Meanwhile, the DD pumps out a delightfully natural, linear bass. The top-end joins the bass with an impressively linear extension through to the upper-treble. This is another earphone that prioritises coherence over wow-factor, excelling with long-term listenability. What the higher price enables is also a very solid technical foundation that ensures this earphone delivers under scrutiny as well.

Bass –

The low-end is very naturally voiced to my ears, exemplifying the qualities of a great DD, but with a less pressurised sub-bass that’s a lot easier on the ear than most designs. Coming from other high-end hybrid and DD models, it may sound a little polite, but in the grand scheme of things I find bass to strike a great balance between upholding a natural presentation and high detail retrieval. The tuning demonstrates both excellent linearity and accurate timbre. Sub-bass extension is strong but again, with slightly reduced emphasis. As such, tight, solid impact and defined rumble remain, if not an especially hard-hitting or skull-pounding slam. A small rise in the mid-bass instigates a slightly fuller note structure and lightly warm tone without a hint of congestion or bloat.

I am also very enamoured with the driver quality. It’s already clear that this is not an aggressive or especially physical DD sound. Rather, the note presentation carries natural attack and decay while upholding good pace, separation and organisation. Driver control is excellent, working in tandem with a balanced tuning to resolve small details and maintain high note definition, despite a slightly warmer and slower decaying presentation. As always, a good BA earphone will provide more definition and agility yet, though at the cost of that lovely natural texture, articulation and overall timbre. Though not authoritarian in presentation or presence, the Homunculus’ low-end provides a highly enjoyable listen and a solid foundation for its sound.

Mids –

Perhaps most contentious, the vocal presentation isn’t perfectly even in its metering nor does it strike the perfect balance of properties that IEMs in this price range commonly do. What the Homunculus instead aims for is an augmented, deliberately coloured presentation that still remains highly natural in tone and voicing. What’s significant to note is a recessed lower-midrange followed by a bolstered centre and upper-midrange before fall off at 4KHz. The net result is slightly diminished and laid-back male vocals combined with forward, enlarged female vocals. As such, it cannot be said that the Homunculus strikes perfect balance in its presentation despite possessing good balance between the three core frequency bands as a whole. Another interesting characteristic is the qualities of said vocals.


Male vocals are mostly natural and well-defined but a touch thin, dry and generally less flattered than female vocals. They remain enjoyable as the extent of these changes is not large, however, the Homunculus does not specialise in versatility as a result. Female vocals shine in the spotlight, bolstered and powerful yet defined and clear, they are both enhanced and showcased to the listener. The 4KHz trough instigates a dense, full image, ensuring that the Homunculus sounds rich and natural in body despite only modest warmth and body permeating from the bass and lower-midrange. As the lower-treble also hasn’t been brought forward, this isn’t a clarity-focussed sound, nor is it a forward or glossy one, and it won’t appeal to listeners prioritising such qualities. Rather, articulation is smooth, forming a coherent presentation with organic notes that strike a superb balanced between definition and density.

Highs –

Amongst the dual estat earphones I’ve tested, the Homunculus easily offers one of my favourite performances; neither as aggressive as the Astrotec Phoenix and EE Valkyrie nor as polite as the EE Wraith or Avara EST-6. The top-end sits in harmony with the midrange, showcasing impressively linear extension into the upper-treble and flattering minutiae with its gorgeous tonality. Indeed, a great estat implementation doesn’t sound awfully different to a good BA-setup. However, considering how long manufacturers have had to perfect their implementation of BA technology, this simply showcases that MMR are providing a mature and well-metered implementation with a natural timbre on top. As a result of its linear delivery, naturally the Homunculus will not appeal to listener’s wanting a crisp and aggressive detail presentation. Still, treble instrumentation is flattered by accurate body, erring just slightly on the thinner and lighter side, in addition to an ultra-clean transient response followed up by similarly natural shimmer and decay.

As the price would suggest, outstanding extension and resolution is to be observed, with convincing sparkle and energy at the very top. Nonetheless, the background is clean and immaculate, delivering excellent foreground/background contrast, in turn, enabling a strongly focused detail presentation in the lower-treble. As such, though never bright, the Homunculus provides copious headroom and heaps of air alongside excellent detail retrieval. They impress with their detail dense foreground whose restrained quantity also draws focus to the earphone’s strong resolving power of micro-details in the background too. This aids the formation of a multi-dimensional soundstage and keen sense of direction. Though not exactly blatant in its expression of its technical prowess, it cannot be denied that the Homunculus offers a very insightful treble response specialising in natural tone and presentation.

Soundstage –

The Homunculus crafts a very spacious stage, with easily out of the head width and great depth too, forming a well-rounded presentation. This is especially so with male vocals and though female vocals are more forward and powerful in presence, they don’t ever come across as intimate or over-forward. There’s convincing depth and excellent lateral projection of backing vocals alongside a very strong centre image to lead vocals. Imaging too is sharp, immersive and holographic though not overtly so like Campfire Audio’s flagships due to its smooth and natural delivery.

Layering is a highlight of the Homunculus, especially noticeable within the midrange. Localisation is pinpoint accurate, forming a very multi-dimensional listening experience on binaural tracks. Separation isn’t quite as good as more neutrally tuned monitors around this price range, though the spacious stage and well-organised presentation surely aids the discernment of smaller details. There is palpable air surrounding and separating each element though the Homunculus ultimately errs on the side of coherence with its fuller notes. In so doing, it provides a spacious presentation with plump, rich yet well-defined if not isolated notes organised into highly defined layers.

Driveability –


MMR don’t state the sensitivity but do note a reasonable 35ohm impedance. This is quite low for an electrostatic design and subjectively, the sensitivity is very good too, especially considering that the top-end provides good presence throughout. The Homunculus, therefore, isn’t as power hungry as most electrostatic designs, requiring just a little more voltage than most high-end BA earphones. Select comparisons below:

Pixel 4 w/DD TC35B: A highly portable, nicely linear source with a slightly higher output impedance. Slight bass roll-off, slightly reduced bass body. Good control, slightly less defined but still enjoyable. Vocals are a touch thinner but remain natural and well-positioned. Slightly more strained female vocals. Intimate soundstage but with accurate imaging. No hiss.

Shanling M2X: Highly recommended midrange source, nice all-rounder with a low OI. Good bass extension, great definition and control, a touch warmer in the mid-bass. Mids are smooth and natural with a strong centre image. Well-detailed top-end, slightly more aggressive lower-treble. Wide soundstage with accurate imaging. No hiss.

Hiby R6: Noticeably thinner and brighter sound. Bass is leaner with sub-bass roll-off though remains highly controlled and defined. Vocals, become a lot brighter and more forward, pushed laterally with reduced body. Highs are crisper and more forward but with reduced body and texture. Intimate soundstage. No hiss.

iBasso DX200 w/AMP5: Excellent sub-bass extension and control with highly defined mid-bass. Mids are clear and well-positioned, more transparent tone, slightly brighter. Treble is very well-detailed, effortless with sharp attack. Very wide and, especially deep soundstage, excellent imaging and positioning. No hiss.

THX789 w/Khadas Tone Board: Excellent sub-bass extension and bass control, slightly more authoritarian and fuller with increased impact. Mids are transparent in tone, natural and well-layered. Highs are very well detailed, sharp attack and excellent resolution. Soundstage is very wide and deep, excellent imaging and positioning, slightly more holographic. No hiss.

Suggested Pair-ups

The Homunculus isn’t especially power hungry in terms of volume, but the Foster DD is certainly more scrutinising of source output power than most. The bass response, in particular, scales with a clean, powerful source, delivering increased authority and definition. The midrange is well suited towards neutral to slightly warmer sources such as the M2X which really reinforces its coherence where brighter sources can sound just a little strained. In terms of output impedance, the Homunclus isn’t overly picky, surely balance suffered from the 10-ohm R6, but a lower value under 3-ohms will suffice here, with only minimal sound signature changes being observed from the DD TC35B. The Homunculus is not at all sensitive to hiss unlike many high-end IEMs. Overall, this earphone has excellent scalability with high-end sources though is more forgiving of mediocre ones than most high-end models so long as the output impedance is relatively low.

Comparisons –


Avara EST-6 ($1100): The EST-6 provides a slightly warmer take on the very popular diffuse-field neutral tuning. Compared to the Homunculus, the presentation isn’t hugely different but certainly more balanced and less authoritarian in the bass due to its all BA design. The Homunculus offers greater sub-bass extension and a more textured, impactful low-end while the EST-6 is even more linear here, just a touch warm in the mid-bass, but with a lighter impact and rumble due to some roll-of in the sub-bass. The EST-6 has a considerably more even-metered midrange with equal focus on male and female vocals in addition to very minimal colouration besides slightly bolstered vocal body.

The Homunculus is more female-vocal biased, noticeably denser and richer yet, but also less accurate in timbre overall as a result; the EST-6 excelling in this regard. The top-end is similar on both, the EST-6 being a touch crisper in the foreground before a darker background, the Homunculus offering a more linear top-end with greater air, headroom and detail retrieval. Its instrumentation has more body and texture and there is more sparkle with better micro-detail retrieval. The Homunculus provides a larger soundstage while the EST-6 has better separation essentially throughout. Both have superb imaging, the EST-6 is a little more stable with its more balanced tuning, that said.

Campfire Audio Andromeda 2020 ($1099): Not in the same price category but a staple product with a similarly, richer sound tuning. The Andromeda is noticeably bassier with more mid and especially upper-bass, forming a fuller, warmer but also tubbier voicing. The Homunculus is cleaner in the low-end, more natural with greater definition and sub-bass extension. Meanwhile, the Andromeda is quicker decaying so though it is fuller, it doesn’t sacrifice too much detail and definition. Through the midrange, the Andromeda is noticeably glossier, warmer but also more articulate and higher in definition. It is also more even metered between male and female vocals though both are noticeably more laid-back when compared to the Homunculus.

Both are naturally voiced too, so where the Homunculus pulls ahead is with its smoother and more coherent voicing, having a more accurate timbre overall. The Homunculus lacks the same clarity and separation but also lacks any chestiness with its cleaner tone and more accurately articulated treble. The Andro here, is more aggressive, detail forward and crisp. It is noticeably brighter than the Homunculus and brings the minutiae more to the fore. Meanwhile, the Homunculus actually has a touch more detail retrieval though it is noticeably smoother in its delivery. The Homunculus also has more separation though both have superb resolution and extension, the Ando providing more sparkle at the very top. Both trade blows in soundstage expansion, the Andro is more holographic, the Homunculus a bit more organised.

Campfire Audio Solaris 2020 ($1499): The Solaris 2020 provides a more w-shaped sound overall and is much more engaging in its execution of said tuning. Its bass is just as deep reaching but more physical with greater presence and more sub-bass bias creating a bolder note and harder slam. Both demonstrate excellent control, the Solaris has a more concise attack, delivering the harder hitting and slightly more defined presentation while the Homunculus is more natural and linear with a smoother texture. Through the midrange, the Solaris 2020 is a touch more forward in vocal positioning and is also more even metered between male and female vocals. It has a neutral tone and more bolstered note body which makes its male vocals especially sound wetter and richer. The Solaris has a higher definition midrange with greater separation and clarity but is also over-articulated.

The Homunculus provides a more naturally articulated sound with a more euphonic, organic tone and larger vocal size. It is altogether less engaging but also considerably less intense sounding and just as resolving once adjusted. This trend continues to the treble, the Solaris 2020 is brighter in both the foreground and upper-treble especially, emphasizing the detail presence region in addition to providing copious sparkle and air.  The Homunculus is smoother, more linear and also more detailed, especially with percussion due to its more accurate rendition of body, and better balance between attack and decay. It has the more natural instrument presentation and subjectively its balance permits greater separation too. The substantially more energetic Solaris 2020, however, does showcase its similarly strong technical prowess more blatantly to the listener. The Solaris 2020 provides a wider soundstage but less depth. Its imaging is more holographic and localisation is just as accurate.

Custom Art Fibae 7 (1100 EUR): I was actually quite shocked by how similarly these two earphone measured, they match up very closely. Of course, there are large differences in listening due to the varying driver types, specifically, the Homunculus is a bit cleaner sounding in addition to being more vocal biased while the Fibae 7 is more balanced and richer in its voicing. The Homunclus offers a tighter and more defined bass, it is also a touch more balanced and cleaner in tone though fairly similar in voicing. The Fibae 7 sounds noticeably bassier despite measuring about the same, it offers an impressively extended, hard-hitting BA bass but at the expense of resolution, being a lot hazier and less textured at the very bottom. Through the midrange, both are vocal forward and slightly biased towards female vocals. The Fibae 7 is a bit warmer and a touch fuller. Both offer very accurate articulation, the Homunclus is more tonally transparent and offers higher definition with its slightly reduced and tighter bass presence.

The Fibae 7 has slightly wetter vocals, they are more bolstered where the Homunculus is not as forward or filled-in, but is clearer and higher resolution. The Homunculs interestingly, is not as forward as the Fibae 7, likely due to its denser voicing, but it is more vocal biased as the focus then shifts to the centre-midrange. As such, instruments do tend to be noticeably more laid-back. The Fibae 7 has a similar top-end presentation being very linear with a small bump for headroom in the middle-treble. The Homunculus has a bit more fine detail retrieval in both the foreground and background while the Fibae 7 offers a touch more bite in the lower-treble which grants it a bit more attack and aggression in its detail presentation. The Homunclus has more sparkle, the Fibae 7 having a darker background with more emphasis on layering over air. The Homunculus offers a larger soundstage, both image very sharply and boast accurate placement. The Homunculus has better separation.

Empire Ears Phantom ($1800): The Phantom is a warmer and more powerful sounding earphone with a more linear tuning and without the forward vocal presentation. It has almost as much sub-bass extension but as above, less texture and information in the deeper registers than the DD Homunculus. The MMR in-ear is also cleaner in its tuning, the Phantom possessing more of a bass bias in addition to a much warmer tone due to its more bolstered upper-bass. Still, decay is considerably quicker on the Phantom so although a touch tubby in voicing, it redeems almost as much detail than the Homunculus overall and isn’t bloated either. The midrange presentation differs quite significantly, the Phantom offering a fuller, warmer and completely filled in vocal presentation perfectly even between male and female in addition to offering a perfectly smooth articulation. However, it is also less forward in its presentation, especially in the context of its more present low-end. The Phantom’s notes are more fully resolved, the Homunculus having that touch of thinness to male vocals in the lower-midrange and a bit more clarity overall.

The Homunculus sounds tonally cleaner though the Phantom has just as much clarity as it has more upper-midrange presence. As such, the Phantom is slightly more articulate and delicate in the upper-midrange while the Homunculus is smoother, denser and slightly flatter. Through the top-end, the Phantom is more aggressive in the lower-treble with a small 6K peak before large attenuation into the middle-treble. The Phantom is a touch more detailed but has a lot less air and sparkle at the top, a much darker presentation. Still, the Phantom offers a very vast stage, similar in magnitude to the Homunculus but with greater width and reduced depth. It has more defined layers and sharper directional cues, however, the Homunculus is more three-dimmensional due to its more rounded and balanced presentation. The Homunculus has greater separation overall, the Phantom is more contrasty but also much fuller and warmer

Verdict –


Much like tales of alchemy, the Homunculus breathes life into music in addition to Sonion’s temperamental electrostatic technology. This is a coloured yet natural tuning, with a rich, powerful female vocal delivery stealing the show. And yet, this doesn’t detract from the superb technical performance in the treble, delivering excellent detail retrieval and headroom. In turn, the Homunculus impresses with its expansive and open soundstage that retains impressive coherence, nonetheless. Positive are also to be found with regards to build and design, the Eletech cable being the cherry on top. However, this is also where the earphone falters, being large and somewhat sharp. Another aspect that may polarise includes the midrange tuning. Though mostly balanced and natural, the male vocal delivery is dry, strained and oddly laid-back at times, the earphone also has a tendency to place vocals first which can detract from instrument portrayal. Ultimately, it’s a shame that the Homunculus has been so heavily overshadowed by its pricier sibling, the Thummim. The Homunculus still comes across to me as a technical achievement, perhaps not an earphone with widespread appeal but one that will no doubt resonate strongly with listeners prioritising a rich, natural presentation. It provides awesome contrast to the status quo, challenging the allure of familiarity with qualities the listener can grow to appreciate.

The Homunculus is available from Metal Magic Research (International) for $1699 USD at the time of writing. I am not affiliated with MMR and receive no earnings from purchases through this link.

Track List –

BoA, Crush – Starry Night

Catherine Feeny – Hurricane Glass

Coldplay – A Rush of Blood to the Head

Daniel Caesar – H.E.R.

Father John Misty – Pure Comedy

Johnny Cash – The Legend of Johnny Cash

Kanye West – ye

Kehlani – Honey

Lorde – Pure Heroine

Mac DeMarco – Here Comes the Cowboy

Mamamoo – BLUE;S

Minzy – Lovely

Missy Higgins – The Sound of White

NIKI – Zephyr

Radiohead – Pablo Honey

Rich Brian – The Sailor

The Cranberries – Something Else

The Cure – The Head on the Door



Ryan Soo

Ryan Soo

Avid writer, passionate photographer and sleep-deprived medical student, Ryan has an ongoing desire to bring quality products to the regular reader.


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