FIR Audio Radon 6 Review: A Spin-off Surprise
We here at About Audio have been mainly featuring the newest products on the market – but today we’re coming back with a familiar yet wholesome, well-acknowledged flagship IEM of FIR Audio, the Radon 6 (Rn6). It’s been a while since we’ve reviewed FIR Audio IEM but so did for them to unveil their new flagship lineup – the Frontier Series, consisting of Neon 4 (Ne4), Kyrpton 5 (Kr5), and Xenon 6 (Xe6). Additionally, there’s a side-kick limited edition that sits similar to the Xe6’s position, the Radon 6 (Rn6) – which will be the one we’ll be reviewing today.
While I believe most audiophiles would have heard about or already be well aware of, giving a brief introduction of FIR Audio – the brand was founded in 2018 in the United States by Bogdan Belonozhko, who has extensive experience in IEM tuning and brand leadership with his past careers with the previous brand, and FIR Audio is currently one of the most well-famed manufacturers of UIEMs and CIEMs. Let’s now begin the Radon 6 review and see how it performs, sounds, and compares with its flagship competitors.
Packaging
The Radon 6 comes in neat, black
packaging. Once opened reveals the IEMs displayed in a foam padding with the rest of the accessories that are accompanied by the IEMs. Other than the earphones, Radon 6 comes with 3 pairs of Whirlwind silicone tips, 3 pairs of foam tips, 3 pairs of ATOM modules, a installing screw for the ATOM modules, a leather case, a FIR Audio sticker patch, a warranty card, and some paperwork.
The box provides the essential accessories that a user would need but I personally would’ve liked to see more variations of types of silicone tips – nevertheless, these eartips match very well with the Radon 6, so I also understand why they’ve chosen these to be the most ideal one to have it included. The overall offerings are almost the same as the M series but now include the ATOM toolkit – which I’ll be explaining and introducing to you shortly.
Matte Black, Carbon-Fiber Earpieces
The Radon 6 sports a full stainless steel body with a matte black finish throughout the earpiece. For the faceplates, FIR Audio applied carbon fiber with gold nuggets and topped them with sapphire crystal glass, giving a nice black-gold look that is stealth but elegant. As for the driver combination, Radon 6 uses 1DD + 4 Open BA + 1 Open EST drivers. Below are the detailed specifications and we’ll be talking more about the technologies used for Radon 6, including these “Open” drivers.
DRIVER SPECIFICATION
1x 10mm Kinetic Bass Dynamic Driver
2x OpenDriver Balanced Armature Driver for mids
1x OpenDriver Balanced Armature Driver for high-mids
1x OpenDriver Balanced Armature Driver for highs (with Sound Reflector)
1x OpenDriver Electrostatic Driver for ultra highs
TECH SPECIFICATION
Freq. Range: 20-20kHz
Impedance: 28ohms
FEATURES
Machined Stainless Steel Shells (UIEM)
Sapphire Glass Faceplates (UIEM)
ATOM XS Interchangeable Modules (UIEM)
Leather Protective Case (Audiophiles)
Free Custom Artwork & Premium Faceplates (CIEM)
Internal ATOM and ATOM X Modules (CIEM)
Aluminum Protective Case (Musicians)
The earpiece shape has slightly gotten larger and heavier compared to their previous M Series but the differences are still marginal. The Radon 6 uses flat, standard 0.78mm 2pin termination which is a change FIR Audio has made since the M5 series which used extruded MMCX connectors, a welcoming transition as the standardized termination for custom cables nowadays has settled to be 2pin connectors. As for the fit and comfort, the Radon 6 offers a snug, tight fit despite the tad weightiness I feel. The nozzles are slimmer than other brands’ flagship IEMs, hence not causing any discomfort despite the tight insertion the Rn6 has.
Techs Behind the Radon 6: Kinetic Bass
Radon 6 is packed with familiar and new technologies— first, the Kinetic Bass. It’s the updated version of FIR’s Tactile Bass technology. Radon 6 features a wide metal mesh built on the inner side for the large 10mm dynamic driver to deliver impact and bass response with the least interference. It’s FIR’s way to conduct strong, high-resolution bass like bone conductor drivers – while Kinetic Bass is far better in performance and efficiency.
ATOM VENTING: Not only for ventilation but also tunable
Another technology of Radon 6 is called “ATOM Venting” which is FIR’s pressure relief system. The effective venting system allows the eardrums to stay in their natural, relaxed position which also means better for your ear canal health and fatigue. On top of this, FIR went a step ahead by adding flavors to the relief system, making the Radon’s sound tunable. The Rn6 comes with 3 pairs of different color modules, which provide different timbre and sound signatures (mostly bass quantity).
For your interest, Radon 6 is available in both UIEM and CIEM and the applicable technologies slightly differ between the two. The UIEM version uses the ATOM XS modules while the CIEM version comes with the ATOM X modules. While their purposes are the same, the amplitude of the impact would likely differ, the ATOM X causing larger differences than ATOM XS (only to my assumption, as I don’t own the CIEM version).
Open Acoustics: Unleashed BA drivers
Lastly, the Open Acoustics system. It’s basically FIR’s “Open Driver” BAs that offer better performance for the higher frequencies. A similar example would be 64 Audio’s Tia™ Drivers. FIR’s Open Drivers are applied for all of Radon 6’s drivers – except the dynamic driver. But then again, the dynamic driver is also fully vented and positioned as near and parallel as possible to the ears, so I suppose all of Radon 6’s drivers are vented in their ways.
Quality 2-Core Coaxial Stock Cable
The stock cable that comes with Radon 6 is an 8-braid SPC cable that is a tad thicker than general stock cables yet incredibly pliable and soft. It’s terminated with flat 2pin and 4.4mm connectors. While the 4.4mm chassis is made of metal while the 2pin sockets and Y-splits aren’t, the total weight of the cable is quite light for an 8-braid cable. It comes with a chin slider for adjusting the tightness of the upper portion of the wires.
Next Page: In-depth Sound Impressions of Radon 6 / How Does it Sound?