In this review we check out the all-new FIR Audio Radon 6 IEM. A six-driver hybrid monitor selling for $3,299 USD.
Disclaimer: FIR Audio supplied the Radon 6 for this review and our honest opinion.
For those that have never heard of the brand FIR Audio, here’s a little introduction. This custom and universal IEM company has a lot of background packed into their short brand-history. Started by Bogdan Belonozkho, former CEO of 64 Audio, FIR has quickly risen to one of the most innovative and sought after brands in the scene.
FIR Audio is the only company – to my knowledge – that produces tube-less custom In Ear Monitors. 64 Audio has been working with tube-less universals, but have never released one of their models as a custom shaped build.
That, however, is not the only thing that makes FIR Audio unique in the field. They also just introduced a new version of bone conduction – called Kinetic Bass. It’s actually a rather simple thought that turned out very well. They just point a dynamic driver right at the concha of your ear, rather than having it fire into it. Thus making you perceive bass vibrations basically coming from the outside. Similar to a speaker performance, but limited to your ears, rather than your whole body. This can also be seen as a sort of bone conduction, where sound vibrations are picked up by your bones and directed to your eardrums. It’s a cool effect and once you get used to it, you develop a kind of crave for it.
FIR Audio’s line-up of products spans from In Ear Monitors (custom and universal) to maintenance gear and other accessories. I have one of their IEM Vac cleaners and think it’s an excellent investment to take care of your monitors. You can find all of our FIR Audio reviews here.
The FIR Audio Radon 6 is a limited-edition universal IEM that builds on their flagship – Xenon 6. Like the number in the name suggests, the Radon is a six-driver hybrid design. It uses a ten-millimeter dynamic driver for lows. This driver is used as a kinetic bass driver, where the sound is directed at your concha, rather than into your ear-canal.
Unlike most companies, FIR does not use sound tubes in their monitors. Their drivers are designed to radiate directly into the sound-path. FIR uses so called OpenDriver Balanced Armature and electrostatic drivers. Think of these as spout-less drivers, where they have a bigger opening for the membranes to radiate.
In the Radon 6 we can find two open BA’s for mids and one open driver for high-mids. The open BA for highs also uses a Sound Reflector. That’s basically a specially designed “mirror” that reflects the sound coming from the hat-less BA into the ear-canal. On top of these four OpenDriver BA’s, FIR uses an opened-up ultra-high electrostatic driver.
The Radon 6 has a rated impedance of 28 Ohms and a measured frequency response of 20Hz to 20kHz. Pretty standard.
Like all of FIR’s IEMs the Radon 6 also is equipped with their ATOM venting technology. ATOM (AirTransferingOpenModule) can be seen as a special port to mitigate ear-fatigue that is often found in traditional, sealed In Ear Monitors.
The Radon 6 is limited to 300 units worldwide and is supposed to be a universal only model. However, there have been a good number of custom Radon 6’s in the wild. So if you’re after a Radon 6 as Custom IEM, make sure to ask FIR nicely.
Radon 6 is available to purchase from FIR or any of their dealers for $3,299 USD.
The Radon 6 uses the same packaging as all other FIR IEMs. You get a genuine leather case, three pairs of Symbio hybrid (silicone/foam) ear-tips and another set of three foam tips. You will also get the full selection of four ATOM XS modules.
These modules vary in their isolation numbers and alter the bass perception. My Radon 6 came with the red module pre-installed. This one offers the least isolation (10dB) and lowest bass volume (-4dB at 20Hz). You will also get black (13dB/-2dB), silver (15dB/0dB) and yellow (17dB/+2dB). With these modules you can fine-tune your Radon 6 per your preference.
For their limited-edition IEM, FIR opted to bring in a special cable. It’s a pure silver cable that uses an oxygen-free copper shielding. No other FIR IEM comes with this new cable, and it cannot be bought separately. The cable itself has seen a lot of praise, and I can only concur. It’s a fantastic addition to this already wonderful package. The cable only has very low microphonics and is not overly heavy on the ear, which is always a big plus for people with glasses.
Per default, the cable is terminated to 4.4mm balanced and as far as I know, cannot be requested in different terminations. Don’t quote me on that one though.
The review continues on the next page.