Build Quality
FIR’s build quality has always been up at the very top and the Radon 6 is no exception there. One of the few complaints I heard about the Xenon 6 was its weight. Some people found it too heavy, and due to the weight, it tended to fall out of the ear. With Radon 6 FIR addressed that issue and stepped away from the stainless-steel housing to an aluminum one.
The Radon 6 comes in a matte black design with sapphire glass face plates. Under the glass you’ll see a gold-flakes infused carbon fiber look. Personally, I think this one just looks great. The same design has been used in their Xenon 6 IEMs, but with golden housing. With the black shells it looks classier in my opinion.
I am always astonished be the size of FIR’s IEMs. Where most TOTL monitors from other companies are getting bigger and bigger, FIR keeps their shell size at a rather small norm.
The build quality of the IEMs themselves is top notch in my opinion. One point of critique however is the ATOM modules. The color on them is just paint. The first time I took out the red module, the paint chipped. The same thing happened to the black and yellow module. This also happened to my Krypton 5. From what I have seen though, FIR solved that issue by anodizing their modules now. Customers with chipping modules should reach out to them for a replacement.
The isolation depends on the selected module of course. The hybrid ear-tips however provide a very good seal and do a good job in blocking out outside noise. But don’t expect these to offer the same level of isolation as a custom IEM or any other sealed monitor.
Sound
First reports of the Radon 6 arose during CanJam New York in February 2023, and it was mostly described as a blend of Xenon 6 and Krypton 5. This was a description that certainly would be up my alley. A monitor that combines the emotions of the Xenon 6 with the details of the Krypton 5? Sign me up!
I was very eager to experience the Radon 6 myself, so when FIR asked me to review it, I haven’t wasted a second to accept.
During the last two months I have listened to the Radon 6 extensively with my Lotoo PAW Gold Touch and PAW 6000, or my Astell&Kern SR35 (review incoming) and my Chord Electronics Hugo 2 and Hugo TT2. The following is a description of how I hear the Radon 6 with the red module installed. I will briefly go over the differences of the black, silver, and yellow module at the end of this section.
Let’s start with the bass.
The Radon 6 has a very organic and dynamic bass, with a focus on sub-bass punch and authority. The kinetic bass driver really does an excellent job here giving me that one-of-a-kind sensation of feeling the bass being delivered to my ears. I did not notice these vibrations as much with the Krypton 5 though, which led me to believe that my ears prefer custom for that matter. With the Radon 6 it’s a different picture though. No idea why to be honest.
Bass has very good body and speed. Weight is on the denser side and with that in mind, it’s normal for it to come across as punchier and more dynamic. Bass comes with high resolution and texture, where you can hear the nuances of different bass notes and instruments. Something I noticed in particular, is how well it renders Cellos and other lower tune string-instruments.
The mid and upper bass are not tuned as forward as the sub-bass section with the red module, which results in an airier and less dark lower midrange. There still is a good sense of warmth in the lower mids, but their body and texture is not as thick as I am used to from the Xenon 6. The Radon 6 has a more neutral tuning, where male vocals have a lighter sound and don’t come across as vibrant or too full.
The tuning of the upper bass and lower midrange makes sure, that the masking effect is kept in place, which often smears over details or covers up other information in the sound. The Radon 6 does not suffer from any of that in my opinion. En contraire, it has an open sounding midrange with excellent levels of space and air. Vocals and instruments all have an emotional sound to them, which features great levels of richness. Saying that the Radon 6 sounds dry would be far from the truth. There is a smoothness in the sound, that makes me personally crave more and more for it.
The keywords for the mids are organic, open, airy, emotional, and smooth in my opinion. The Radon 6 bundles all that with very high resolution and top of the line quality imaging. The Rn6 creates a wide image, where it reaches excellent levels. In terms of depth, I feel that it could still do better, as the room it creates feels a bit limited.
Jump ahead right here for more sound!
