Fir Electron 12 (E12) Review – Dynamo

Pros –

Easily serviceable housings, Excellent build quality, High-quality balanced cable included, Hugely impressive dynamics, Excellent resolving power, Strong end to end extension, Very spacious soundstage, No wearing pressure

Cons –

Separation could be better, Some may find the bass too bombastic or too thick, Lacks sparkle relative to high-end hybrid/BA designs

Verdict –

Unabashedly coloured, fun and vibrant, the E12 is a paragon of energy, offering a well-realized V-shaped tuning with excellent technical ability.

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About Fir Audio –

Fir was founded in 2018 by Bogdan and Alex alongside their friend Daniel. If those names look familiar, it’s because the team have spent the last 2 decades making IEMs at 64 Audio. Fir was founded to continue the legacy of high-performance IEMs whilst adopting the latest technologies. Their first round of IEMs, the M-series targeted professional musicians and audiophiles whilst creating the groundwork for Fir’s later models. The Frontier series was released 2 years later introducing kinetic bass, ATOM XS, Open Acoustics System (the company’s take on open, tube-less drivers) and Rigid Technologies which allowed the IEMs to be serviced.

Introduction –

When the E12 was first announced, we were given a name and silhouette but little else. Speculation suggested a 12-driver all-BA model, however, Fir subverted this by announcing that it would contain a single 12mm dynamic driver instead. In my discussion with Vlad, he explained that the U18t was the brother’s end to the driver war and that the brands under their lead would work towards optimizing lower driver counts. Reducing complexity increases consistency, aids ease of repair and in some instances, also streamlines achieving the company’s desired sound. The E12 is a fitting response and their first attempt at a single dynamic-driver model. Despite the vastly different tuning process, the brothers sought to develop a true high-end design focusing on the surrounding acoustic design of the shell just as much as the dynamic driver itself. The technologies pioneered by the M-series make a return in the form of tactile bass, ATOM and SwapX with the addition of modular faceplates and a new 8-braid cable out of the box.

The Electron 12 (E12) is available for $1799 USD. You can read all about it and treat yourself to a unit on Fir Audio’s website here.

Disclaimer –

I would like to thank Vlad from Fir Audio very much for his time explaining the technologies behind Fir’s products and for organising a review of the E12. 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.

Contents –

• Page 1: Intro, Unboxing, Design
• Page 2: Sound and Source Pairings
• Page 3: Comparisons & Verdict

Specifications –

• Drivers: 1x 12mm Electro-Dynamic Driver
• Frequency Response: 20 Hz – 20 kHz
• Impedance: 16 Ohms

Behind the Design –

12mm Dynamic Driver

The design started with a 12mm dynamic driver. Though not exclusive to Fir, the entire acoustic structure surrounding it was engineered to deliver their intended sound so the E12 sounds unlike any other IEM. The driver itself was chosen specifically and each is scrutineered to ensure stringent quality control and channel matching. Being a single-driver design, the E12 is phase-coherent too.

SwapX

Fir’s branding for any modular part of their IEMs, this blanket pertains to the 2-pin connectors, faceplates, and chassis of the E12. Specifically, the 2-pin connectors are rated to 1000 connections featuring a quadrant design that reduces the risk of loosening. It’s also serviceable using a set screw. In fact, so is the entire IEM as the entire shell is modular, secured with two micro screws. The final implementation is the faceplate which secures magnetically into the outer shell permitting customization to personal, tastes.

ATOM

A venting system that relieves the pressure caused by an in-ear design sealing within the ear canal. It helps to lower pressure on the eardrum and reduce listening fatigue. It also reduces the occlusion effect whereby self-generated sounds such as vocalization, swallowing and chewing are emphasized to the listener when their ears are covered. ATOM also serves to improve soundstage space and imaging.

Tactile Bass

The very lowest frequencies are tactile as opposed to auditory which is the reason why headphones offer a superior bass performance to IEMs which interact less with the outer ear. Recently, IEMs have implemented bone conduction drivers to augment this, however, Fir is using the driver itself coupled to the housing to achieve a similar effect. The E12’s driver reverberates with the entire solid shell to enhance low-frequency extension, perception, and performance.

Unboxing –

The E12 comes in similar packaging to the M-series before it, providing a professional impression. Sliding off the outer sleeve reveals a Fir branded hard box. Inside are the IEMs within a foam inlet with the carrying case just below. It’s a leather unit with a hard skeleton and suede interior that provides impact and scratch protection. Inside is a foam insert containing the ear tips alongside a suction cup that can be used to swap the magnetic faceplates. The E12 comes with 3 pairs of memory foam tips and 3 pairs of hurricane silicone tips too alongside a cleaning tool. I appreciate that Fir also includes an iron-on patch for clothes with Space Force branding on it, a nice touch. I also received 2 additional faceplates with a black and ivory texture that provides a cleaner aesthetic to the more visually distinct Abalone shell faceplates installed from the factory.

Design –

As opposed to the more exotic Frontier series, the E12 follows the more understated design language of the previous M-series. The silhouette is broadly similar besides a slight rounding of its profile and a slight increase in width. It’s a 2-piece machined aluminium shell with a modular, serviceable design and a sand-blasted deep indigo finish. The tolerances are tight with a palpable seam between the two halves but well-finished edges and curves alongside a perfectly even texture throughout. The faceplates are removable and attach via small button magnets. An outer lip on the shells helps them to seat perfectly everytime. I didn’t experience any accidental loss of faceplates during my testing as they fit snugly and securely within the housings.

The adoption of 2-pin connectors offers substantially wider compatibility with aftermarket options than the RCX connectors used before. In addition, the connectors used by Fir offer an especially tight connection that inspires confidence. Fir has introduced a new 8-wire cable touting pure silver conductors with copper shielding. The clear jacket showcases a rich colour and offers excellent flexibility with zero memory or springiness. This makes it an ergonomic delight. The pre-moulded ear guides and black metal connectors also inspire and microphonic noise is minimal due to the over-ear fit style. The overall build quality and cable provide a very positive impression of quality that lives up to the premium price. The modular faceplates are nicely implemented and look just as natural as any non-modular design within the IEMs.

Fit & Isolation –

The ergonomic experience very much mirrors the M IEMs given the similarities in overall profile and construction. The E12 is a little wider but this isn’t hugely noticeable during wear. As the profile is slightly smaller, the E12 may even be slightly more comfortable for those with smaller ears, especially if you found the housings too tall previously. Otherwise, the nozzle is nicely angled and elongated to provide a solid seal and fit. Ear tip choice is imperative as the ATOM modules relieve pressure. As a result, driver flex is not apparent, and comfort is enhanced as occlusion is reduced alongside the sensation of wearing pressure.

However, ATOM also decreases the retention of the earphones due to the loss of suction. I had best success going down one size with AZLA’s Sednafit ear tips that have an elongated stem, producing a deeper fit. Due to the long nozzles, you are able to experiment with larger tips granting a shallower fit and smaller tips providing a deeper one which opens another avenue for sound tuning. Despite the openness, isolation is very good and well above average for a dynamic driver in-ear. They isolate almost as much as many sealed designs especially with more isolating foam eartips making these a good choice for public transport and even travel.

Next Page: Sound Breakdown