Surprising Single Driver Performance | FiR Audio Electron 12 Review

Surprising Single Driver Performance | FiR Audio Electron 12 Review

Single dynamic driver IEMs have a reputation for natural timbre, powerful bass, and warm but often bloated tunings. FiR Audio has a similar reputation for making IEMs with natural, impactful delivery, and adding a little extra power in the low end. With that in mind, you might anticipate – like we did – that the single-DD FiR Audio Electron 12 would be somewhat of a bass monster, but rather than exaggerated impact, FiR aimed for cohesion, resolution, and balance. Does e12 break the stereotype and hit the mark as a more detail oriented single dynamic driver IEM?

FiR Audio Electron 12 Review iBasso DX320 Max

Build and Design

e12 achieves its sound with a single 12mm “electro-dynamic” driver along with FiR’s Tactile Bass system. Tactile Bass conducts some of the vibrations of the driver through the shell, turning the entire shell into a sort of secondary transducer for extended low bass. The shell itself is machined aluminum, and the faceplate is removable with FiR’s SwapX system. You can purchase new faceplates to replace the original and give the IEMs a new look.

FiR Audio Electron 12 Review Cable Highlight

The package includes a leather-wrapped case, the cable, eartips, and some assorted case candy, like the FiR Audio Space Force patch. The cable has 2-pin connection with a 4.4mm termination, and really goes above and beyond expectations. The cable has a premium feel that matches what brands like Effect Audio and PW Audio are doing in the $1000 price range, and features a pure silver core with copper shielding.


My first impression of Electron 12 was that it was somewhat bright, due to the lively, energetic treble that stood out in the first few tracks. After a bit more listening, and some tip changes (I ended up sticking with the included foam tips, rather than my typical choice of SpinFit), I found it to instead be stunningly balanced, with well extended highs, deep bass, full mids, and a sense of speed that was shocking for a 12mm diameter driver.

Fit is essential to the bass, as the Tactile Bass system needs a close fit to deliver the vibrations of the shell. Without getting good contact, e12 is lacking in the impact and extension in the bass. With all the pieces in the right place, e12 has great impact, rumble, texture, and detail in the low end.

The midrange is loaded with detail, delivering clear vocals and natural timbre that extends up into exceedingly lifelike highs. The extension of the treble has a nice splash and sizzle in cymbals that feels similar to the speed of EST drivers, making you almost doubt that this is all being accomplished with a single 12mm DD.

e12’s imaging feels like somewhat of a contradiction. On the one hand, the placement of instruments and voices feels somewhat intimate and up close, but on the other hand, it doesn’t feel constricted or closed in. The impression is that e12 gives you a large soundstage, but it puts you on the stage with the instruments, rather than a few rows back where the band would feel more spaced out.

Listening to Hiromi’s “Sonicwonderland” I noted a great balance in the way it achieved both cohesion and separation between the low synth play and the bass guitar. Even during fast doubling runs, e12 clearly delineated the instruments in the ensemble. The song also shows off how the more focused impact in the midbass combines with the more powerful low extension and rumble to create an experience that bass lovers can appreciate, without letting bass dominate the mix. The upper end of the mix feels articulate and resolving, offering plenty of nuance in the cymbals while horns remain slightly smooth at the top.

On “Sad But True” by Metallica, e12 hits you with a huge guitar sound, and a sense of power from the band as a whole. There’s a little bit of extra snap in the snare that lends to the aggression in the song. This is also a track where the bass is often lost behind the thick guitars, but Electron 12 offers the separation in the low end to give you each note of the performance. With this track in particular, there was a strong “studio control room” feeling: as if the band was just in the next room while you’re getting the raw live feed as the music is being made.

FiR Audio Electron 12 Review w/ DX320 Max No Cable

Moving into “Bridge Over Troubled Water” by Simon and Garfunkel, e12 again balances a natural, musical delivery with a stronger sense of insight into the music. The small imperfections – whether in the recording or digital transfer – are noticeable, but don’t stand out in a negative way. Instead, those flaws in the recording add a sense of character and humanity to the performance. As the song builds into the final verse, Electron 12 captures the dynamic shift, and provides a sense of intimate imaging that’s both up close and wide open.

Comparison: HIFIMAN Svanar ($1999)

While the high-end IEM field is currently dominated by multidriver IEMs, there are still a few strong single dynamic driver options, HIFIMAN Svanar being a notable recent one. Like Electron 12, Svanar opts for a more balanced, neutral sound, rather than the exaggerated warm or bassy tuning that many associate with single DD IEMs. Are either of these worthy to be crowned the single DD king?

FiR Audio Electron 12 Review HIFIMAN Svanar Comparison

In terms of the build and design, Svanar offers a more impressive presentation, but on closer examination, e12’s build is a bit stronger, with the cable in particular being notably better than Svanar’s cable. Svanar has a lot of strong elements – like the polished brass underside of the shells – but doesn’t provide the same premium feel as e12. While the build and design elements aren’t as strong, Svanar also offers an easier fit, while e12 has a longer stem, along with the need to be deeply inserted to properly capture the Tactile Bass.

In terms of sound, there are some strong similarities, while the differences are more subtle. For both, the overall presentation is highly natural and balanced, and the imaging combines some sense of larger space with some elements feeling more intimate. In the bass, e12 has a deeper extension and a stronger rumble in the subbass, while Svanar has more midbass impact. Svanar also has a little more energy in the upper treble, while e12 has a more even extension from the mids into the treble.

In the imaging, Svanar presents a wider stage, and a bit more space and separation in general. e12 feels closer in with a more rounded, three dimensional presentation. So while Svanar is more spacious, e12 has a bit more realism in the way instruments are positioned and presented.

FiR Audio Electron 12 Review HIFIMAN Svanar Comparison

Purely in terms of sound, both were excellent, and the difference was a matter of preference for one or the other on specific tracks or albums, rather than a clear advantage or disadvantage to one or the other. If you had to break it down to a couple bullet points, Svanar has wider soundstage, and an easier more comfortable fit, but e12 has better craftsmanship, better bass extension, and a little more bang for your buck.

Final Thoughts

Electron 12 offered new surprises throughout my time listening to it – from uncovering the true potential in its bass, to catching small details I’d never expect in this sort of design. In the end, I found e12 to be a great balance of revealing detail and engaging musicality. At its core, that engagement comes from the honest, lifelike presentation that sets e12 apart, and makes its single driver performance stand out among a sea of increasingly complex designs.