Fir Audio Electron 12 (E12)

SwapX tech from SpaceX Bunny!

PROS: durable metal shells with user replaceable and customizable SwapX faceplates, internal Atom module, big expanded soundstage, powerful articulate bass, clear detailed upper mids/treble, quality cable and other accessories.

CONS: universal only, non-replaceable Atom module, cost of additional faceplates.

The product was provided to me free of charge for the review purpose in exchange for my honest opinion.

Manufacturer/product website: Fir Audio. Available for sale directly or authorized retailers like Bloom Audio.

Intro.

Considering the success of Frontier Series, including Radon 6 joining its lineup early this year, for some reason I didn’t expect another new release from Fir Audio that soon, especially since their sub-brand Bellos Audio also started to pick up the momentum with its new X-series of CIEMs. Then, out of the blue early in August someone spotted a mysterious “Electron 12” IEM from Fir Audio at AV Show in HK. Following their previous model numbering, I got excited and replied on Head-fi in Fir Audio thread with “… E12 got to be 12BA model, right?”. The thought of 12mm single DD driver never crossed my mind. So, when I was corrected in the forum by others, it all made a perfect sense. A big part of Frontier series was the Kinetic bass, so why not trickle-down some of its performance into the next budget-friendlier release?

Of course, single driver design could be tricky since you have only one building block covering the entire frequency range. Obviously, we are not dealing with the same “kinetic” dynamic driver. But does it have the same Fir Audio bass DNA and able to scale up across the whole FR? After spending a few weeks with this latest release from Fir Audio and being able to analyze its performance, let’s find out what Electron E12 single 12mm DD IEM brings to the table.

Unboxing and Accessories.

The overall packaging dimensions and the unboxing experience of E12 are similar to other Frontier Series IEMs. Here you will find a compact box with a custom white sleeve and the cover artwork focusing on a colorful faceplate reflecting its SwapX tech. The back of the sleeve has a detailed summary of the key features. Inside, there is a secure foam tray for IEMs and the cable, a genuine leather protective round case, Fir Audio traditional “space force” sticker, and other accessories including a set of foam eartips (S/M/L), a set of Whirlwind eartips (S/M/L), a cleaning tool, and a… tiny suction plunger.

E12 is only available as universal monitor, though we have seen a similar introduction with RN6 which later started to offer CIEMs. But unlike Frontier series unis, here you can replace the default set of faceplates and order other customizable ones (for each side) from a big selection of materials and finishes available for their CIEMs. You can even customize it with your own artwork. I received my review unit with another set of custom finish faceplates, and those could be ordered separately at any time, I believe for $149.

The included cable uses the same wires as RN6 cable, pure silver core with OFC shielding. But unlike RN6 with its soft pliable PVC insulation in dark brown finish, E12 cable has a clear insulation to reveal the beautiful copper tone of its oxygen-free copper shielding. The cable still features 2 thicker conductors going to each side, gold-plated balanced 4.4mm termination with a comfortable grip metal housing connector and Fir Audio logo, a matching finish metal y-split and a sliding chin-slider with a logo, pre-shaped clear earhook heatshrink, and 2pin connector for non-recessed shells with a compact straight metal housing and corresponding L/R marking on inside and “ears” on outside. The cable is comfortable to wear and has minimum microphonics.

Design.

As I already mentioned, while all the previous Fir Audio IEM model names had a numerical reference to a number of drivers, here the number refers to a driver size, Electron 12 (E12) stands for a single 12mm Electro-Dynamic Driver. With an average impedance of 16 ohms and isolation of -17dB, considering it already comes with an internal ATOM (air transferring open module) pressure relief system, you can safely assume it uses the equivalent of “+” Gold Atom module. The Atom module is not removable/replaceable, it is fixed, with its vent located close to 2pin connector. For those who were driving themselves crazy switching between Atom modules while trying to decide which one to use, this will probably be a blessing.

The exterior dimensions of E12 are not too far from Frontier series IEMs (like RN6), featuring machined aluminum solid shells design with a dark purplish finish. As I already mentioned, they also feature SwapX design where faceplates are attached magnetically to the shell and can be easily removed and replaced using the included plunger tool. You can even lift them up with a fingernail along the edge. But despite of how easy these to remove, they stay on secure, even after a hard shaking of shells. Once you remove the faceplate, you can see two screws underneath, part of SwapX assembly of modular shell design for easier serviceability. And the same goes for 2pin connector, as part of their Rigid Tech introduced in Frontier series, here you can replace 2pin connector socket using set screw.

A lot of thought went not only into the sound design of these IEMs, but the actual design of shells and their components, to makes sure it will last and if needed, serviced in the most efficient way. But the selection of components is also important, like durability of 2pin connector, rated for up to 1,000 connections and featuring a quadrant socket design for a better compatibility with different cables and to avoid the risk of loosening after multiple re-insertions. The nozzle features the same design as in Frontier Series, to make sure eartips stay on secure without sliding off even when you are sweating. But you will not find a mesh nozzle screen cover since it was decided that driver sits far away and will be easier to maintain with a cleaning tool or even a vac, this way, less chances of screen getting clogged. For me personally, I do miss a mesh screen cover.

Fir Audio refers to their 12mm electro-dynamic driver as “tactile bass” driver. Frontier series Kinetic 10mm bass driver had dual conductive mechanism, both through air-conduction via nozzle and bone-conduction from the back through a large mesh cover, directly into your ear cartilage. E12 12mm driver is bigger, transmits through air-conduction only, and utilizes the entire solid shell as its acoustic chamber to reverberate the sound. Basically, it is intricately coupled with IEM chassis which, according to Fir Audio, turns it into a secondary transducer. Also, coupled with a built-in “Gold” Atom module, you should get the max isolation which results in a deeper lower end extension.

The fit.

Just like Frontier series, E12 universal shells sit comfortably inside my ears, sticking out just a little bit. The nozzle has an average length, not too long or too short. The shells are very lightweight, about 8g each, making you forget they are even in during the extended listening sessions.