M-Fidelity SA-43 Review: Transparency from Norwegian Fjords


M-Fidelity is a custom in ear monitor manufacturer located in the south of Norway. It’s founded by Alf Middelthon, who previously worked for Starkey – a large hearing aid company. After leaving Starkey, he founded M-Fidelity and brought his designs to the new company. M-Fidelity has interesting designs including customs with switches, and different acoustic hoses than the industry standard. In addition, Alf offers plug-in earphones called ERM series with exchangeable filters. In my opinion, these earphones are really interesting in terms of getting different sounds from one single ear-mold.    

The company also offers the HF series hands free earphones as well as 7 different custom in ear monitors such as SA-33, SA-32 Live and the entry level SA-12. Alf is a very responsive and helpful person. I had no issues in the process of getting the SA-43. He usually replies to mails within 24 hours

Build Quality, Cable, Accessories and Internals:

The reviewed SA-43 has an acrylic shell filled with silicone. This is an option; you can get a silicone filled shell for a small additional fee. The silicone filling offers better protection against damage, but I personally don’t feel inclined to test its limits. There are some bubbles in the shell due to the silicone, but nothing major to complain about since it is inherent to the nature of the method. The craftsmanship is quite good except for a few minor mistakes, some very little bulges on the surface. The faceplate is a bit thick but carefully placed on the earphone andthere is no overflowing from the corners.

The sockets’ craftsmanship and placement is good, but I find them a bit too tight and it was a bit difficult to remove the cable at the beginning. On the other hand, that tightness extends its durability and keeps sockets connected for a long time. The wax filters seem to be of high quality, and are replaceable with a tool included in the package. There are 8 replacement filters included with the earphone and the diameter of the filters is wide enough to clean wax with a cleaning tool.

There are two switches on the faceplate of SA-43; a blue one for low frequency boosting, and a red one for mid frequency presence. The switches work quite well and their build quality is good. However, it is best to be careful while inserting or removing the earphone, since these little things are a bit fragile.The canal part of the SA-43 is a bit long, extending a few millimeters past the second bend. The canal is the longest among my other custom in ear monitors. The length may disturb some listeners, but I have no complaints about the canal of the SA-43. In my opinion, silicone filled shells and long canals provide a very good isolation. I have no seal break with jaw movements, and I can honestly say that the SA43 has the best isolation among my customs.

The SA-43 has a 3-way crossover system with 4 balanced armatures.  Two of them are bigger than the others, and there is an interesting coating material on the bigger armature drivers. In contrast to the industry standard, the SA-43 has more rigid and non-transparent acoustic sound tubes. They remind me of the material of PVC windows.  The stock cable of the SA-43 has standard quality and is just like a Westone or Unique Melody type of cable. There is no issue about the cable so far.

The SA-43 comes in a mid-sized outer box with a carbon fiber look. The included accessories are a cleaning tool, small carrying case, replacement filters and their tools, and an owner manual. However the size of the carrying case is a bit too small to protect the switches from damages. A bigger place to put the earphones might have been more suitable for better protection. Both the outer box and carrying case provide a premium feeling, which should be inherent to a TOTL CIEM’s packaging.  


The SA-43 offers 4 kinds of sound signatures from a single custom in ear monitor: Flat, more dynamic, mid oriented and bass heavy. In general, the SA-43 has a sound that is very close to neutral when the switches are off. With either both switches off or on, it has great timbre and outstanding transparency.

Low Frequency:

When the bass switch is off, the low frequency has a presentation closer to being tight rather than splayed. The low frequency of the SA-43, especially its mid-bass, has a bit warmer tone compared to the neutrality of the midrange .The sub-bass has quite fast and powerful attacks, and hits from a medium to large area of impact. Its hitting to depth ability is very good and creates a good stage dimension. The tone is not the most natural among my other earphones, but is quite good for a flagship and there is no armature kind of artificial or rough rumble. The mid bass, which is located in the middle of the stage, has a balanced presentation along with the sub-bass; it doesn’t tighten the stage and the spaciousness remains the same when the switches are off.   

With only the bass switch on, the sub-bass becomes more powerful and hits from a larger area on the stage with a bit more dynamism. However, the mid-bass, which becomes quite prominent, gives a bit too much warmth to the overall spectrum and fills the stage with warm air; the spaciousness gets lost when bass switch on. Additionally, with only the bass switch on, the overall spectrum becomes a bit smoother, but at the cost of losing transparency and its ability to create timbre. When both switches are on, the overall presentation becomes more balanced and transparent again, with a more dynamic and lively note recreation. The overall low frequency resolution and texture cannot reach the level of my other flagship CIEMs, but it is quite good for a CIEM priced at 820 USD.

Mid Frequency:

When both switches are off, the mids are quite natural, full-bodied, and flat. Even if the mids aren’t the cleanest, they are neither laid back or too forward. Some might find it a bit dry, but the overall tone of mids is close to neutral with great timbre. Instruments have an exceptional realism and it is almost impossible to talk about a veil on the presentation. Often too much transparency may become fatiguing by thinning the overall recreation of notes. The SA-43 creates both thick and thin notes quite good, especially with both switches on. It also has an outstanding transparency without brightening notes; and doesn’t fatigue the listener at all.

With only the mid presence switch on, the SA-43 becomes a mid-oriented earphone and instruments are presented a bit forward on the stage; the mid-bass presentation becomes laid back with a bit less overall dynamism. Due to the less prominent low frequency and lack of smoothness which is normally added to the whole spectrum by the mid-bass tone, the mids may become unnatural and note creation becomes a bit thinner compared to the other switching variations. Vocals and instruments are a bit more forward with slightly better resolution, but also a greater tendency to sibilance.

When both switches are on, the mids are exceptionally transparent and realistic. The presentation becomes quite powerful, more resolved and dynamic.  This is my favorite setup on the SA-43, with a more deeply enveloping sound.With both switches on or only the mid presence switch, the detail level is quite good among my other CIEMs, but the resolution is not the best when both switches are turned off.

sa43-3 ates

High Frequency:

The SA-43 represents highs with clean, transparent, thick and full-bodied notes. Highs are neither bright or fatiguing; the detail level is good with overall a very true tone, but resolution and extension levels are not excellent for a flagship. On the other hand, the overall speed of highs is good and it can keep up with fast metal tracks as well as drums solos in jazz fusion tracks.  

With both switches on or only the mid presence switch on, highs are more prominent and alive. Highs remain natural when both switches are on, but are smoother with both switches off.

Soundstage and Instrument Separation:

The SA-43 uses the stage dimensions very good; it doesn’t have an overly wide or deep stage, it remains within the limits to create great coherence and focusing. It also has a quite spacious stage with both switches off. When both switches are on, instruments are a bit closer to the listener; even so, it remains spacious and creates a more enveloping sound with better depth stage compared to its flatter response. Instrument separation is very good in every single switch variation. Even if the background isn’t the blackest or most stable, instruments are very well positioned and separated with enough distance to create a very realistic presentation.

Source Matching and Driving Issues:

The SA-43 is moderately hard to drive, so it needs a powerful source in order to reach to its full potential. I’ve tried it on several sources such as the Fiio X3K, QLS QA360, HM901 with Minibox, Lotoo Paw Gold, and IPhone 6. Pairing with a low quality or low powered source results in a lack of transparency and spaciousness. But when a powerful amplification/source is used, the SA-43 becomes quite impressive.

 Final Words:

Its midrange might not be the cleanest, nor is its overall resolution the best among my other CIEMs (especially with both switches off); but the M-Fidelity SA-43 is one of the most transparent and true sounding custom in-ear monitors that I’ve ever heard. It sets itself apart by creating a very realistic listening experience due to its coherence and outstanding timbre..

Website and Ordering Information: https://inearmonitoring.wordpress.com

The SA-43 price: $770 USD (Detachable cable) , $730 USD (Non-detachable cable) plus shipping. 

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Ates Berberoglu

Ates Berberoglu, aka MikePortnoy at Head-Fi, started listening music on his father’s old HIFI system, when he was a child. His audiophile journey has begun under the wings of a dynamic driver IEM and he now mingles with high-end portable systems. He mostly focuses on custom in ear monitors, digital audio players and aftermarket IEM cables.


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