Although the company was founded five years ago in 2018,FiR soundthe founders have been driving innovation in the IEM market for years with 64 Audio. Their latest innovation, the Kinetic Bass, was the highlight of their Frontiers i seriesRadon6is the latest in the range, aiming to deliver a captivating mix of accuracy and musicality that is as comfortable in the living room as it is on stage. Is Kinetic Bass just a gimmick? Does the Radon 6 offer more than just nice-sounding technology to potential buyers?
Construction and design
FiR Audio's core design language stands out from most IEM worlds as it uses an aluminum chassis with clear 64 Audio roots instead of a molded enclosure and spices it up a bit. The case is lightweight and ergonomic and it was easy for me to fit the different ear tips well. The Radon 6 package includes a set of standard foam earbuds and a set of Symbio Hybrid earbuds, which basically looks like someone inserting a foam ear tip into a silicone ear tip.
The Radon 6 is a triride with six drivers: one dynamic, four open balanced armatures and one EST. While the front panel looks pretty typical, turn the IEM over and you'll notice that the dynamic driver has a unique ventilation system. The dynamic driver hits the ear directly, enhancing the physical experience of good bass, delivering a sound that is somewhere between typical dynamic presentation and bone conduction.
FiR Audio has also developed its own pressure management system for IEMs called Atom. The Radon 6 version is called the Atom XS and uses small modules that can be replaced with an Allen key. There are four color-coded options: red is 10dB isolation, black is 13dB, silver is 15dB, and gold is 17dB. While I had a hard time really seeing the difference in aperture size for each module, I preferred red and felt it gave the strongest sense of openness and realism that are Radon 6's main features.
It seems like there are only two different types of tuning these days: 1. Slight deviations from a common target curve (e.g. Harman Neutral or Diffuse Field), 2. Experimental tunings that excel at one particular thing. The Radon 6 largely falls into the first category, but there's also an experimental element to it as the FiR open acoustic system and Kinetic Bass transform the sound experience while staying close to the familiar Harman-style tuning.
Bass Radon 6 is one of its greatest strengths. The bass feels precise, with strong texture and great detail in low-end instruments, but what really sets it apart is the Kinetic Bass system. It's a simple idea - a dynamic driver with a large opening aimed directly at the earlobe - and the results are spectacular. Kinetic Bass gives your bass a natural sense of punch, rumble and depth without the need to over-emphasize or over-emphasize the bass. This way you get the best of both worlds: bass that is powerful and physical, but also remains accurate and realistic.
The midrange should be grateful for this bass innovation, as it allows for a strong extension of the mid and sub bass without having to create a bass shelf that overwhelms the midrange. The midrange offers strong detail, natural timbre, rich layering and excellent reproduction of vocals and instruments.
At the top end, you get a treble that gives the sound an open, airy feel, with great definition and clarity, while preventing fatigue. There's also sharpness in the treble, with an amazing sense of resolution. The more open nature of the design, with the Atom XS system and vented dynamic driver, also seems to help reduce potential treble fatigue, allowing the Radon 6 to deliver strong treble presence without being overly bright or harsh.
While the EST's balanced midrange and treble are well-tuned, it seems the key element that elevates the Radon 6 from "a really well-tuned IEM" to "exceptional, exceptional flagship performance" is the Kinetic Bass. It's not just about the bass performance itself, but how this type of bass tuning makes room for other positive aspects of the Radon 6's performance.
The soundstage is another highlight here, and the width is exceptional, but it doesn't offer as much depth as the width. Likewise, the imaging seems very strong from left to right, and the overall presentation of the image is three-dimensional and holographic, but the front-to-back imaging just lacks depth. The Atom XS modules certainly have an impact here, as most of my impressions were gathered with the more open red and black modules, but the silver and gold seemed to increase the width a bit while adding depth.
To find some reference bass tracks, I reached for LoFi Girl's "Study lofi" playlist and found "Snowflakes" by Pandrezza. There were three main elements of the track that really stood out: the kick, the bass and the muffled snare. The kick has a low physical punch, while the snare hits high but elicits a similar physical response somewhere near the intersection of the highest open BA and EST pickup. Kinetic Bass in Radon 6 gives the bass an incredibly deep, textured rumble that feels like it's vibrating your entire skull. Of course, there are melodic elements too, and they're nicely layered, adding breadth and depth to the sound, with the Radon offering crisp detail and a three-dimensional feel. But we're not really on this playlist for tunes. We're here to bash our ears with bass, and the Radon 6 delivers a lot of boorishness.
Often IEMs with great bass and some bass emphasis fail when it comes to older recordings or classic rock, but that's not the case with Radon 6. From vocal presentation to delicate piano, Radon 6 delivers realistic rendering with an open, spacious "Life on Mars by David Bowie. There's also a good sense of the song's dynamics, both in the presentation of the vocals and in the band's performance right up to the final chorus. The largely acoustic nature of the recording allows the Radon 6 to demonstrate its effectiveness with simpler instruments and natural sounds.
This is also the case with a classic piece like Stravinsky's FinaleApartament FirebirdThe Radon 6 brings a wealth of detail and character to any instrument, with a textured string bend and fast brass stab. The bass can flex its muscles in the powerful thump of the timpani at the climax of the song, and the Radon 6 delivers an amazing display of dynamics along with amazing coherence and coherence as each piece of the ensemble has a distinct sense of separation. while feeling like a unified whole.
Współpraca: Campfire Audio Trifecta, Empire Ears x Astell&Kern Odyssey
Seeing how the technology underlying the Radon 6's bass performance is an important aspect of sound, I wanted to compare it to other IEMs that offered some level of innovative design or low end. To achieve this we haveAudio trifecta by the fire, famous for its triple dynamic pickup configuration, and, which uses a bone conduction transducer for bass and offers tuning not too different from the Radon 6 in general.
In general tuning, the Trifecta is clearly aiming for a bit more warmth than the other two. The Odyssey really has a big "wow" effect with that extra punch and more lively overall presentation, while the Radon 6 feels a bit more natural, with a less obvious sense of deliberate emphasis in some ranges.
All three have some unique soundstage and visual characteristics. The Trifecta has an absolutely huge soundstage and visuals that feel like on-ear headphones. The Radon 6 gets a little extra width and air with its more open design, but it doesn't offer the same level of spatial feel as the Trifecta. The Odyssey most closely resembles a really great IEM soundstage, with good breadth and depth and strong imaging, but nothing that particularly stands out, or at least doesn't stand out in the same way as the Trifecta and Radon 6.
In bass, the Radon 6 hits somewhere in between the two. Where the Trifecta has a bigger, rounder mid-bass and the Odyssey has a mix of punch and deep rumble, the Radon 6 is not as round and warm as the Trifecta, nor as emphasized in the sub-bass as the Odyssey. The Trifecta definitely flirts with bloat a bit more than the other two, but the Odyssey's bass can bleed a little too, with the Radon 6 having the most controlled bass of the three.
As you delve into the sub-bass, you'll discover an almost unreal sense of depth Odyssey can fathom. The Radon 6 has a strong low-bass feel, but without extreme depth. There is a slightly stronger sense of texture in the Radon 6 that makes some low bass instruments feel alive, and the specific way it delivers low bass through the Kinetic Bass port gives me an all over mind feeling while the Odyssey's powerful sub bass feels more local.
When you add it all up, the Radon 6 really falls in the middle: the Odyssey offers the most lively, exciting sound, while the Trifecta is warmer with a more relaxed overall presentation. The Radon 6 offers a more natural sound that is more organic than the Odyssey, but without entering the Trifecta's luscious, warm territory, and more technical than the Trifecta, without matching the Odyssey's frenzied prowess.
It comes down to
As a relatively new brand building premium flagship IEMs, FiR Audio needs to not only create a great product, but also provide some kind of differentiation that will allow them to stand out in an increasingly competitive market. With the Radon 6 - and the entire Frontiers series - FiR Audio delivers not only great sound, but also a real innovation in Kinetic Bass. Combining superior tuning and design and a new level of IEM listening experience with Kinetic Bass, the Radon 6 clearly stands out in today's IEM market.
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