[REVIEW] M-Fidelity SA-33 Custom In-Ear Monitors
Sep 25, 2013 at 4:35 AM Thread Starter Post #1 of 2


100+ Head-Fier
Jan 9, 2012

M-Fidelity is a custom in-ear-monitoring and hearing-protection company based in Norway. They were formerly known as “Starkey Norway”, but since their lab’s contract with Starkey has ended they have became “M-Fidelity”. The company has quite a few CIEM offerings in their line, ranging between a large range of prices. Their flagship is called the SA-43 and it has 4 balanced-armature drivers inside of its shells, but there is a twist to that – the user can choose if he wants to turn on the 4th driver in order to change the sound or not. The product of theirs that I am going to write about in this review is called the SA-33. It is very similar to their flagship, and in fact it differs only by not having the 4th BA-driver, meaning that it is actually an SA-43 without the user-controlled sound.

Technical Specifications:

Impedance: 50 Ω

Sensitivity: 104 dB @ 1mW

Frequency Response: 35 – 18,000 Hz

Cable Length: 125cm

Driver:  3 Balanced-Armature drivers in a 3 Way-System crossover

Building Time

It took M-Fidelity 3 weeks to complete the CIEMs from the time my impressions’ arrival to their office. I have sent the CIEMs back later for a re-shell (not their fault, my impressions were not perfect) which took them around 2 weeks to complete (they have managed to solve the problem perfectly).


The included large-carrying case serves as the packaging, so there’s nothing to write about here.


The SA-33 comes with a nice amount of accessories (compared to other CIEMs), which are as follows:

Large Zippered Carrying-Case- This is the first thing that you’ll see once you’ll open the package. It is a quite large (might seem a bit too large for some) zippered case made of a black-colored leather-like material. It has a lot of space inside of it, in which you can find places to put each accessory that comes together with the SA-33 along with a portable music player too.

Small Zippered Carrying-Case- this is a hard shelled case which provides great protection to the CIEM, and unlike the case that I’ve mentioned above, this one is actually portable, and you can put it inside of any pocket in your pants without a problem. Inside of it there are two mesh-covered storage-sections in which you can put some small accessories.

Soft Carrying-Case- this case is made of the same material that the large case is made of and it looks quite similar to the case that comes with Xears’ IEMs.

3.5mm to 6.35mm Adapter- you can use this adapter if you want to connect the SA-33 to a professional amplifier or to an electric-piano, for example.

Two Cleaning Tools- one of the tools has a brush in its top while the other one has a metal-loop there.

Replacement-Filters- there is a little paper-box inside of the large case in which there are 8 replacement filters, which are pre-attached to the replacement tools.

Building Quality & Design

The SA-33 next to my LCM-5​

The customization options for the design are quite limited in comparison to the previously reviewed LEAR LCM-5 CIEM; there are only a couple of options for the shells color one of them being translucent red & blue and the other one being clear (transparent. As for the faceplates, they can be black, white, clear or smoke colored and there is also an option for them to be made of ply-wood (which costs an extra); M-Fidelity also lets you to choose if you want to have a hard-wired cable or detachable one, which costs an extra as well. My own set has black faceplates, clear shells and a removable cable. Like many other CIEM manufacturers, M-Fidelity too lets you have something laser-engraved on the shell (without an extra cost). I chose my shells to have my initials on them. The quality of the engraving is only decent, as parts of some of the letters that are engraved on my shells are slightly erased.

The building quality of the acrylic shells seems to be quite great, with them being very solid and tough. M-Fidelity has a special extra-cost option (which my pair has) which I haven’t seen any other company offer – filling the shells with silicone; doing so will provide the drivers a lot of protection because of the silicone’s shock-proof nature, as well as improving the isolation by quite a bit in comparison to a regular acrylic-shelled CIEM. There is also a small disadvantage that happens due to filling the shells with silicone, which is having some bubbles inside of the shells, just like with some silicon CIEMs. The cable’s sockets are flush and there are side markings just under them on each shell. There are two bores in the tip of the SA-33 which have a user-replaceable wax-guard filter inserted inside of them (there are 8 replacement filters that come with the SA-33).

The cable’s connection pins​

The braided cable that comes with the SA-33 has the Y-Split placed a bit too high in my opinion, but apart from that it is identical to the one that comes with most of the CIEMs: it has a memory-wire portion, it will oxidize and it has a quite large 3.5mm jack that will not fit all of the devices which have a protection-case on them.

Comfort & Ergonomics

The comfort is standard for an acrylic-shell CIEM. The shells are heavier than your regular acrylic CIEM-shells because their silicon-filling, a thing which sometimes causes a faster fatigue compared to my LEAR LCM-5, so you might feel like needing to let your ears rest every few hours when using the SA-33. The included cable has a memory-wire portion which can sometimes be annoying and can sometimes help, but that depends on every single user.

Isolation & Microphonics

The silicon-filled SA-33 offers an amazing level of isolation and it comes extremely close to my Etymotic hf-5 (and is a lot better than my LCM-5) in reducing outside-noises, which is definitely impressive. Microphonics are minor and should not really bother you.

Sound Quality

The gear that I have used during the reviewing process includes my 4th Generation iPod Touch, which is loaded with mostly iTunes Store M4A files and 320 KBPS file. For some of the time I’ve listened to the SA-33 directly out of my iPod, while I’ve also tested it with amplification, provided by Firestone Audio’s Fireye HD & HA amplifiers, connected to the iPod’s dock input via a generic LOD to 3.5mm adapter. Due to the SA-33′s not so high sensitivity it needs a bit more power to reach to your regular listening volume and to reveal its true potential, so I will recommend to listen to these CIEMs out of a powerful source or to connect them to an amplifier instead.

The three Balanced-Armature drivers which are inside of the SA-33′s shells produce a natural, airy, spacious, balanced, neutral and transparent sound-signature. We will now move on to a more detailed description of every one of the sound’s parts:

Bass- The SA-33′s bass is a bit above neutral in its amount, but the BA-driver is able to produce a larger amount of bass if it is needed in a certain track (the SA-33′s bass amount and impact are both quite large than the LCM-5′s ones) . Like the amount of the bass, also the impact is largely based on the track that is played – if it calls for a solid impact then the SA-33 would easily re-produce it, but if it doesn’t then it won’t. The extension is ok but not too much above that; that is in my opinion the largest disadvantage of the SA-33′s bass, and I wonder if the SA-43′s 4th driver might be able to fix this. There appears to be a nice punch to the lows as well as a quite fast speed. The bass feels tight and controlled as well as being well detailed and clear.

Midrange- the midrange is flat, transparent and neutral. Its placement is in the same line of the frequencies, meaning that it is not forward and nor recessed. The timbre is excellent; it is truly one of the best that I’ve ever heard in an IEM/CIEM – it is just so natural and realistic. The detailing is great while not being too aggressive and “thrown at your face”. The main feeling that I get from the SA-33′s midrange is that it is musical and it engages the listener into the music.

Treble- the treble is as neutral and flat as the midrange, and it is not bright but neither recessed. It is clean and clear and it has a great extension, managing to reach some quite high frequencies with both the lower and the higher treble being well detailed (not as much as good as the detailing in the LCM-5′s treble, but it comes quite close to it). There is also a lot of airiness in it as well as a good amount of sparkle too. Sibilance is pretty much non-existent in the SA-33′s treble, which is very good since it makes the potential fatigue due to the sound to be very small.

Sound-Staging and Instrument Separation – in my opinion, the sound-staging is the best thing that the SA-33 does. Its sound-stage is just HUGE both in depth, height and width in comparison most of my other IEMs/CIEMs. There is a lot of spaciousness and the imaging is amazing. The instruments are so well placed around that it creates an extremely realistic feeling and the presentation sounds very 3 dimensional. Instrument separation is impressive as well, and it can be compared to that of my LCM-5.

Final Conclusions

The SA-33 proves to be a great CIEM, and I can say that I like it as much as I like my (beloved) LCM-5. The LCM-5 might be a bit better from the technical point of view, but the SA-33 is more engaging and some might think that its sound is more enjoyable than the LCM-5′s one. If you are searching for a large sound-stage CIEM then this one is for you; it has one of the largest sound-stages that I’ve heard in an IEM/CIEM. In addition to the excellent sound, we also have here a great and solid building-quality, which ensures that you’ll be able to enjoy your earphones for a long time without worrying of malfunctioning. I was impressed by the great effect of the option to fill the shells with silicon on the isolation, which [when going for that option] is very close to the isolation of Etymotic’s IEMs. A sweet extra is the nice and generous accessories package that comes with this CIEM, which is very useful.

Purchasing Info- the basic hardwired SA-33 is sold at a price point of NOK 5192 (which translates to around USD 880) while the basic detachable-cable version of the SA-33 is going to cost you (which translates to around USD 920). Adding some of the options that I have mentioned would cost a bit of an extra (the silicone filling would cost around 27 more dollars and having a ply-wood faceplate would add 40 more dollars to the total cost). You can purchase the SA-33 by contacting M-Fidelity – you can find their contact info here.

This review was reposted from my reviews & news website "It's A Headphones Thing". Check it out for some more IEMs and Headphones reviews. http://iahpt.wordpress.com/

Jul 5, 2014 at 12:57 PM Post #2 of 2
Thanks for the review, I just contact them :)

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