FiR Audio Xe6: The Great Frontier

Frontier Series 

Before we turn our focus to Xe6, let’s cover off some of the interesting new technologies that FiR engineered into the entire Frontier Series, which also includes the ‘entry-level’ Neon 4 (Ne4), and ‘mid-level’ Krypton 5 (Kr5). 

Kinetic Bass. Big bass in IEMs has always been something of an oxymoron. After all, when we think of big bass, we think floor-standing speakers or subwoofers, massive dynamic driver cones moving large volumes of air as low-frequency waves that we ‘feel’ as much as we hear. 

As you can imagine, this trick is a little more difficult to pull off with a driver smaller than your pinky nail. Not that IEMs can’t reproduce impressively ‘big’ bass – heck many IEMs do so better than headphones with drivers ten-times their size. But getting that much bass air to ‘move’ in such a small space is generally detrimental to just about every other frequency that comes after, often resulting in a thick, muddy sound that’s not particularly hi-fi. 

Kinetic Bass literally flips the script on traditional dynamic driver designs. Using an outward-facing dynamic driver beneath an open-vented port above the IEM nozzle, low frequency sounds are transmitted directly into the inner-ear through the bone cartilage, in a process known as bone conduction. This allows the full spectrum of bass energy to pass through your ears in the same way that it does using full-size speakers, through air and bone conduction, which, in theory at least, makes the bass feel more immersive, extended and ‘real’.

Other IEMs use bone conduction technology to vibrate sound waves through the shell or ear tip, but no other IEM that I know of uses it specifically for the foundational bass frequencies through an open port, changing how we experience bass given the inherent physical limitations of IEM.

ATOM Venting. FiR’s Air Transferring Open Module is not a new technology for Frontier, but rather an existing technology adapted to better fit the new Frontier universal shells. ATOM is essentially a vent that releases air pressure trapped inside the ear canal, reducing fatigue and all but eliminating the reflex that causes your eardrums to protect themselves against prolonged exposure to loud sounds. 

That’s not to say ATOM removes the failsafe built into your ears, but rather eliminates one of the main causes of listener fatigue, allowing you to listen for longer without the build-up of dangerous hearing-impacting pressure. It’s also not the same type of venting used in most ‘vented’ IEMs, which only serves to remove the pressure that builds up inside the IEM itself due to the air movement of the various drivers. That type of venting protects driver performance; ATOM protects your hearing.  

Other benefits of ATOM include the perception of a larger soundstage due to improved airflow and reduced isolation. The flipside is exactly that – reduced isolation – so you’re more likely to hear environmental sounds using the most open ATOM modules. Of course, changing the level of isolation also changes the perception of certain frequencies, which means you can tweak the tuning of Frontier Series IEMs by swapping out different ATOM modules. 

Open Acoustics. Most IEMs use drivers connected to sound tubes that direct sound through the nozzle into your ears. Frontier Series IEMs use a combination of three elements: open drivers, a sound reactor and a sound reflector.

All the drivers inside Frontier Series IEMs are open drivers, so they radiate sound directly outward into the IEM chamber. The sound waves pass through a sound reactor, which hones and refines it without resorting to dampening or filtering that would otherwise degrade the signal. There’s also a single high-frequency open driver that sits outside the main drivers (which are in the nozzle shaft), and fires at a sound reflector directed straight at the ear canal. 

The end result of the different parts that make up the open acoustic system is a smoother, less brittle and highly dynamic sound, with excellent extension at both ends. 

RIGID System. If there’s one aspect that’s often overlooked in the modern industrial design of many IEMs, it’s build quality. Thankfully this doesn’t apply to Frontier Series. Not only is the artistry, material quality and assembly of the Frontier IEMs exemplary, they also use a series of highly-resilient ‘RIGID’ parts to improve reliability.

These include what FiR claims to be the most durable 2-pin connector in the industry, rated for 1,000-plus connections, and a quadrant design that prevents the 2-pin socket from coming loose. Each Frontier Series nozzle is also fitted with a RIGID snap screen, an acoustically transparent steel mesh screen that prevents dirt and debris from reaching the IEM’s internals, and can snap on and off for easy replacement.  

Two other RIGID technologies are used exclusively on the custom versions of Frontier IEMs, which we’ll hopefully get to review in a future article. 

Taken together, these four technologies – some evolutionary, others revolutionary – make FiR’s Frontier Series IEMs some of the most advanced premium monitors you can buy, at least from a usability and longevity perspective. Each IEM goes beyond the core technologies, with varying driver configurations and tuning, to deliver a different sonic experience. 

However, where Ne4 and Kr5 ‘toe the line’ in terms of the more conventional tonal and technical performance expected of high-end monitors, Xe6 tears up the script with a risky attempt at utterly unconventional. Does it work? Let’s find out. 

Continue to Xenon 6…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


Leave a Reply

Your email address will not be published. Required fields are marked *

Recent posts