Well-balanced, Very high detail retrieval, Almost perfect isolation, Fast, controlled bass
Some finish imperfections, Reasonably bright lower-treble won’t suit some listeners
The SA-50 impresses with its balanced signature, great resolving power and immense passive noise isolation.
Hailing from Norway, M-Fidelity has developed a devoted cult following with their custom in-ears and reference-style tuning. Their SA-50 represents the latest and most premium model in Alf’s SA line of earphones. It forgoes the sound tuning switches of the SA-43 before it but introduces an additional driver, 5-balanced armatures in total. It was tuned with balance and detail retrieval in mind and implements a 4-way passive cross-over in addition to anti-resonance sound tubing in order to achieve this. The SA-50 comes with a slightly increased asking price of NOK 7990, or around $1000 USD. You can read more about the SA-50 on M-Fidelity’s Facebook page and order a pair for yourself here.
I would like to thank Alf from M-Fidelity very much for his quick communication and for providing me with the SA-50 for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.
M-Fidelity have no online customizer, instead, every order is configured through a form available on M-Fidelity’s website to be mailed with the buyer’s ear impressions. M-Fidelity have a handful of options with 4 aesthetic options; engraving, shell, faceplate and cable. Users are also able to choose between a fixed and removable cable in addition to silicone filling that provides additional noise isolation. It’s an efficient process overall and though there’s no real-time visualiser, Alf provides photos of most combinations on his website. The level of customizability is substantially more limited than most competitors but all of the more popular colours and materials are available.
The M-Fidelity earphones have a nice accessory set, convenient for travel and with extras to keep the earphones at optimal performance. They ship within a large zippered hard case with faux carbon-fibre texture. Inside is a more pocketable hard case containing the earphones themselves. Another compartment houses the other accessories, a shirt clip, cleaning tool, replacement nozzle filters and a tool to replace them. Basic papers detailing the specifications and correct steps to replace the filters lie within the top compartment.
Design & Build –
The M-Fidelity earphones are only offered in acrylic and their fit, like any custom, depends on the ear moulds provided. Unfortunately, my first set of moulds were slightly off, however, Alf was quick to build a new set with some revised ear moulds. In both instances, the build process took just over a month and I received frequent updates including photos of Alf’s progress, terrific stuff!
The SA-50 exudes a more hand-finished quality than most custom in-ears, serviceable but far from perfection. Even on my opaque review unit, small bubbles were apparent along the surface and there was a very visible and palpable seam running along both faceplates. That said, I didn’t find any of these imperfections to compromise seal and all edges were nicely smoothed to aid comfort, these are simple aesthetic annoyances.
Ergonomically, the most notable aspect of the SA-50 is its long nozzles that extend a few millimetres further than my other customs. In addition, the earphone’s two sound tubes protrude from the end of the nozzles as opposed to most competitors that have a recessed output. It should also be noted that the SA-50 has protective metal filters fit to each sound tube, a thoughtful addition not included on many custom in-ears that should help to extend their lifespan.
A tool is included in the box in addition to replacement units should they become damaged or blocked. The SA-50’s design is, no doubt, ideal from an acoustic standpoint, minimising ear canal resonances, however, Alf does compromise perfect comfort to achieve this. Over time, my ears did adjust, but the SA-50 never quite disappears in the ear like Custom Art’s more smoothly sculpted designs to name one example.
Still, no hotspots formed and discomfort never pushed me to remove the earphones. Furthermore, isolation is almost perfect as a result of their deep fit. I also opted for the silicone filled shells, another option unique to M-Fidelity, that provides a slightly denser feel in the hand and further increased isolation compared to hollow units. The SA-50 is, therefore, ideal for frequent travellers and attenuates noise to an almost dangerous degree during daily commute.
Should buyers opt for a removable cable, and I highly suggest you do, the SA-50 will come equipped with the highly popular 0.78mm 2-pin connector system. They’re not recessed, permitting use with a wide range of aftermarket cables and very firmly hold the attached cable, ensuring no lost earpieces and reliable audio. The stock cable is a fairly standard 4-wire braided unit. It’s flexible with memory wire ear-guides but also fairly thin. Only the colour can be altered and all cables are terminated with a right angle 3.5mm plug. I would recommend the beige, black or grey cables as the transparent cable oxidises and greens fairly quickly.
The SA-50 has a well-balanced signature with a linear, neutrally sized low-end, clean midrange and moderately forward high-end. Focus centres especially around the lower-treble, providing a more aggressive detail presentation. Meanwhile, a touch of additional mid-bass fullness provides body and solidity to its sound. The SA-50 also avoids any brightening of its midrange, it is smooth and appropriately dense if not especially full. This culminates to provide a sound that is very revealing without coming across as thin, strident or peaky.
The low-end of the SA-50 is likely the main characteristic that lends people to describe it as reference monitor-like in its tuning. Bass is linear, neutrally sized and without an iota of flab, bloat or muddiness. Sub-bass extension is its main shortcoming; it suffers from slight roll-off and fails to deliver the same depth and slam of dynamic driver and even many armature-based competitors. Still, bass depth is adequate to engage, aided by a punchy mid-bass that redeems note body and prevents the SA-50 from veering into coolness.
Its upper-bass tuning is also well-considered, and very neutral in quantity, contributing towards a clean and neutrally toned presentation. What especially impresses is the SA-50’s speed and control. Decay is on the faster side and notes are focused. Bass is highly defined and impact is tight, unveiling high quantities of detail. The SA-50 doesn’t provide huge depth and slam, nor is it outstandingly dynamic. Instead, it impresses through its ability to deconstruct even complex tracks with surgical precision, enabled through high control and great separation.
Mids are generally even and well-present with small sculpting infusing a hint of additional engagement. And though not perfectly linear, the SA-50 has one of the best-compensated signatures I’ve tested, delivering appropriately sized vocals and instruments with mostly accurate placement and body. Bass spill is non-existent and tone is very neutral. Body is very slightly thin due to a few dB of lower-midrange attenuation though this is counteracted by an upper-midrange trough that provides additional density; contributing towards a smooth and resolving vocal reconstruction. As the centre midrange sits slightly behind, vocals are placed a touch behind instruments.
On the contrary, upper-mids receive a small bump, enhancing clarity and ensuring vocals never become overshadowed. The extent to which the SA-50’s midrange deviates from neutral is small, but large enough to provide its own unique character. That upper-midrange dip isn’t sharp like some cheaper earphones, so it doesn’t overly affect treble body or higher female vocals. Still, some over-articulation is present due to the SA-50’s emphasized lower-treble though vocals aren’t thinned out nor is sibilance exacerbated. As a result, timbre isn’t perfect, but still very accurate on a whole and the SA-50 achieves a presentation that is simultaneously clear and well-separated yet smooth and well-bodied.
Like the midrange, highs aren’t perfectly even, but very well-tuned, excelling with detail presentation and organization. It is a bright earphone, but the SA-50 impresses with its gradual emphasis and clean background. Post upper-midrange dip, the SA-50 climbs to emphasis until a gentle 6KHz peak. It’s actually not especially bright in the grand scheme of things, but treble stands out by comparison to the earphone’s attenuated upper-midrange. Still, as emphasis is gradual and the emphasized frequency range is wider than most, treble instruments retain pleasing body while upholding a crisp presentation with focused attack. The SA-50 excels with acoustic tracks and its detail retrieval is very high in addition to being forward in presentation.
Cymbals don’t sound splashy and strings remain pleasantly smooth. This can be partially attributed to a slightly attenuated middle treble that provides a very clean background. Meanwhile, slight upper-treble emphasis redeems air and shimmer in addition to enhancing sparkle and micro-detail presentation. This style of tuning also draws focus to the SA-50’s very strong treble extension, delivering excellent resolution. On initial listen, I was inclined to label the SA-50 as aggressive. However, the nature of its treble tuning makes it rather slightly analytical, and a well-executed example of such. Moreover, as its background is clean and extension is strong, its sound is immensely detailed with plenty of air all the while remaining composed.
With strong extension, the SA-50 has a fairly spacious soundstage though its balanced tuning doesn’t exacerbate its sense of scale as more sculpted earphones can. Its dimensions are nicely rounded, stretching slightly beyond the head in both width and depth. Imaging is terrific, instruments are accurately placed and easy to discern. Vocals are well-centred and never become overly distant or forward whether male or female. Highs standout slightly more than other frequencies though they are precise and deliver pinpoint directional cues. Separation is a prime strength of the fast, neutrally toned SA-50. Each element is easy to isolate and, due to its clean background, very clearly defined layers and accurate instrument placement, the SA-50 doesn’t sound diffuse but well-collected and composed.
The SA-50 has a 30ohm impedance combined with a 102dB sensitivity granting it above average sensitivity. As a result, it’s not as prone to hiss as most high-end IEMs though it is still quite source sensitive in other ways. In particular, the SA-50 benefits from a high current source and is very affected by output impedance. Select pairings below:
HTC U11: The U11 is one of the better smartphones out there, it has a lower output impedance in the low single digits, though it’s still enough to skew some earphones. Bass extension is worse and texture is smoother, not quite as defined. Midrange is darker with more laid-back upper-mids. Highs are crisp but thin with muted air, lower detail retrieval. Claustrophobic soundstage with poor layering, okay separation.
Shanling M0: Nicely balanced sound. Slightly smoother bass texture but well defined and tight. Even midrange with appropriate density, upper-mids are a touch laid-back and tone is very slightly warmer. Highs are well detailed and extended, resolution is very pleasing. Soundstage dimensions are moderate but imaging is sound and separation remains high.
Hiby R6: The R6 has a 10-ohm output impedance. Compared to the low-impedance sources below, it provided a clearly darker, more muted top-end. Bass is untouched, clean and well defined with a little extra mid-bass fullness. Meanwhile, mids are darker, female vocals are more laid-back and clarity is reduced. Highs are also considerably more laid-back, the earphones retain plenty of crispness, but treble becomes thinner and air is muted. This produces a more claustrophobic soundstage.
Fiio X7 MKII w/AM3A: Nicely balanced sound. Well-controlled bass, impactful and nicely defined, a touch warmer. Pleasing midrange with greater density, refined and smooth vocals, appropriate positioning. High resolution, slightly enhanced air. Above average soundstage expansion but with defined layers and coherent imaging.
DX200 w/AMP5: Nicely balanced sound. Well-controlled, tight and impactful low-end with great definition. Mids are even and appropriately dense, nicely refined. Well-placed vocals. Treble is very detailed and well-extended. Resolution is very high and air is enhanced. Spacious soundstage with defined layers and great separation, excellent imaging.
Campfire Audio Jupiter ($800): The Jupiter is more similarly balanced but with a notably darker upper-midrange. It has better sub-bass extension combined with more quantity. The Jupiter has a touch of mid-bass emphasis that sustains into the lower-midrange, making it noticeably warmer and more full-bodied than the SA-50. That said, its low-end isn’t quite as clean and separated, nor as defined though it is more dynamic. As it also has more centre midrange, vocals are noticeably more present with greater body but also less clarity. The Jupiter’s upper-midrange dip explains this, it’s quite dense and smooth in its presentation.
However, it picks up energy quite quickly, gradually climbing to an emphasized lower-treble. It isn’t quite as bright up top as the SA-50 but brighter than neutral. It’s very well detailed, delivering more treble body if slightly less crispness. The Jupiter has a more neutral middle-treble, delivering greater air. It extends just as well up top and, combined with greater upper-treble emphasis, has more sparkle and a more aggressive presentation of micro-detail. The Jupiter has a larger soundstage and it images just as well if not better due to its more even midrange and lower-treble. That said, it lacks the same separation of the SA-50.
Custom Art Fibae ME ($820): The ME has a distinctly fuller, darker sound. Its sub-bass extends considerably further and it has a lot more emphasis. The ME also has more mid-bass but declines through its upper-bass into a similarly attenuated lower-midrange that prevents bass spill. It’s a lot fuller, its decay is also slower so it’s considerably less defined and detailed in return for greater dynamics. Midrange tone is a lot warmer and body is fuller on a whole on the ME. Vocals are actually slightly more present and it employs a similar upper-midrange emphasis preceding a trough to imbue clarity without thinning out body. As such, the ME is fuller and denser but also more vocal forward, it’s very lush and unapologetically so.
The ME has a more neutral high-end that sits in-line with the midrange. Lower-treble has a hint of additional crispness while middle treble is slightly attenuated to produce a darker, clean background. It has an uptick of upper-treble energy similar to the SA-50 but lacks the same detail presence and air. Despite this, its extension and resolution are almost as good, it’s simply smoother and considerably darker in its presentation. The ME has a similarly spacious stage but it is considerably less separated due to its fuller notes and warmer tone. Imaging is quite strong on both, the ME suffers from over-enlarged bass notes that cloud its placement while the SA-50 has over-forward treble at times.
Campfire Audio Atlas ($1300): The Atlas is a lot more V-shaped, clearly tuned for engagement over balance. Its sub-bass is significantly more extended with huge emphasis while its mid-bass remains lifted for additional body. Conversely, the Atlas employs steeper attenuation of the upper-bass and lower-midrange to separate its midrange from its big bass. Its bass is a lot more dynamic, but also less defined and controlled. As such, its midrange isn’t much fuller, though it is slightly full-bodied in isolation. The Atlas also has similar vocal presence due to a centre midrange push though the rest of its midrange is more recessed.
It lacks the upper-midrange dip of the SA-50, sounding just as clear but less dense and grounded in its voicing. The Atlas similarly has an emphasized high-end, it has an earlier 5KHz peak, delivering a slightly more organic detail presentation. The Atlas has more middle-treble delivering greater air and its upper-treble is similarly tuned, emphasizing sparkle and micro-detail retrieval. Both extend terrifically well, the SA-50 has slightly better micro-detail retrieval and resolution, however. The Atlas has a larger soundstage but it is less organised and separated than the SA-50’s.
Empire Ears Phantom ($1800): The Phantom is noticeably darker and fuller. It has significantly better sub-bass extension in addition to greater sub-bass quantity. The Phantom similarly has a touch of mid-bass emphasis but it has more upper-bass, instigating its warmer tone and its low-end is generally fuller and more dynamic. The Phantom is more even through its midrange. As such it isn’t as clear and as separated but is more coherent and accurately bodied. Its vocals are also more present. The Phantom has a similar degree of lower-treble emphasis, it sustains emphasis a little longer before a significantly sharper attenuation into its middle treble.
As such, it’s crisp and its foreground is more detailed than the SA-50, but its background is a lot darker and it has none of the air and shimmer of the SA-50. Similarly, it lacks any upper-treble emphasis, lacking pristine clarity and sparkle. That said, extension is similarly strong, delivering high resolution and the Phantom sounds more composed and coherent overall. It has better imaging and a larger soundstage, especially with regards to width. The Phantom does not separate as well as the SA-50 due to its warmer, fuller sound.
Noble Audio Katana ($1850): The Katana is a brighter earphone, especially with regards to middle treble its midrange is more forward. The Katana has super bass extension combined with slight emphasis. Its decay is very natural for a BA, producing strong dynamic the SA-50 cannot match. The Katana has less mid-bass and upper-bass however, the Katana is appreciably more detailed down low with similar speed and even higher control. The Katana has a similarly recessed lower-midrange, I would posit from measurements that it would sound a lot thinner than the SA-50 but that is not the case in listening. It has more vocal and upper-midrange presence, producing greater clarity.
It employs a similar upper-midrange dip for density but it’s more progressive than the SA-50, its female vocals sounding more open and extended but just as smooth and refined. The Katana has a brighter high-end with similar lower-treble emphasis that sustains into its middle-treble. As such, its background is brighter and it has a lot more air, shimmer is also more appropriate. The Katana extends further at the very top, delivering higher resolution and similar micro-detail retrieval. The Katana has a more spacious soundstage and even greater separation.
The SA-50 is a very nicely balanced earphone and also a resolving one. However, around its asking price, so are most earphones. The SA-50, therefore, differentiates itself through its strong detail retrieval accentuated by its detail forward style of tuning. Especially impressive is that it executes this style of tuning without thinning out or becoming overly aggressive and fatiguing. Listeners will also find much to love within the SA-50’s smooth midrange and clean, hyper-defined bass. It is not an earphone for those prioritising a rich, dynamic and extended low-end or those averse to treble. However, for buyers searching for a balanced signature, great resolving power and immense passive noise isolation, the SA-50 is a strong high-end offering with some unique characteristics.