Astell&Kern Pathfinder In Ear Monitors review

The musical landscape, as we know it, would be a far duller place without the coming together of different artists to create amazing, and occasionally unexpected collaborations. Think: Queen and David Bowie (Under Pressure), Run-DMC and Aerosmith (Walk This Way), or even good old Kylie Minogue and Nick Cave (Where The Wild Roses Grow). As well as being responsible for producing some memorable hits in the studio, collaboration has also created some gems at the other end of the musical “food chain” - from time to time, audio manufacturers decide to team up and lend their respective know-how and brand “cred” towards a common goal: a one-off project that blends the DNA from each brand into one unique result. 

South Korea’s Astell&Kern is no stranger to brand collaborations, having lent their name and expertise to many an audio partnership over the years. As well as being renowned for their range of brilliant Digital Audio Players (a.k.a “DAPs”), Astell&Kern has also made waves in the world of personal audio through a series of carefully chosen and inspired collaborations with some of the biggest names in the headphone and IEM world, including Beyerdynamic, Jerry Harvey Audio, and more lately with IEM-heavyweight Campfire Audio with last year’s release of the Astell&Kern AK SOLARIS X In-Ear Earphones

Not wanting to rest on the laurels of the AK SOLARIS X, Astell&Kern has teamed up again with the Portland-based IEM manufacturer to deliver an even more advanced in-ear offering courtesy of some never-before-seen hybrid driver technology, plus (of course!) Astell&Kern’s signature visual flair that touches every audio product that their logo graces. 

The result? The brand-new Astell&Kern Pathfinder In Ear Monitors, which are available now for $3199 at Addicted To Audio. Sticking with the theme of “collaboration”, an all-new hybrid driver array has been chosen for the new Pathfinder which sees an interesting blending of Dual 10mm Dynamic Drivers to handle low and mid-range frequencies, a brand new Dual-Chamber BA Driver which has been specially developed by Knowles to handle key parts of the mid-range, plus dual Balanced Armature drivers for high frequencies inside each carefully sculpted “Night Sky”-coloured anodised aluminium and stainless steel shell. 

Astell&Kern Pathfinder key specifications:

Transducer type

[High] Custom Dual Balanced Armature Drivers + T.A.E.C.

[Mid] All-New 'Dual Chamber' Balanced Armature Driver Technology from Knowles

[Mid-Low to Sub-Bass] All-New Dual Custom 10mm Dynamic Drivers paired with Radial Venting Technology


2.5mm Silver Plated Copper Cable

3.5mm Silver Plated Copper Cable

4.4mm Silver Plated Copper Cable

Material / Design

Aluminum shell with "Night Sky" black anodised finish

Hand polished stainless steel threaded spout

Stainless steel "Mountain Peak" design

Frequency response



94dB @ 1kHz 13.49mVrms


6.2 Ohm @ 1kHz

Total Harmonic Distortion

Less than 1%

What’s in the box?

Every Astell&Kern product I’ve owned or reviewed over the years has received the first-class packaging and accessory treatment, and the Pathfinder certainly continues in this vein - it’s one well-appointed pair of IEMs. 

Inside the box, we have a leather zip-up “purse” that ought to be familiar to any owners of other Campfire Audio IEMs. The case provided with the Pathfinder is terrifically well-made and is lined with a nice soft faux wool-like material to avoid any abrasions or scratches to your IEMs while carrying them around. Two mesh pouches are also provided - a larger one for stashing your cables and other accessories in, plus a smaller one with two divided sections to house each IEM shell safely in to avoid them rubbing against each other or your cables whilst in storage or on the go. 

Speaking of cables, Astell&Kern has really outdone themselves here. Not only is the cable provided with the Pathfinder probably my new favourite IEM cable, but there are three of them! The four strands of the Pathfinder’s silver-plated OFC copper “Litz” cable have been assembled in a flat “ribbon” instead of the usual braided arrangement. This flat-style construction is great at avoiding kinks and tangles and is covered with a nice soft transparent plastic that is free of the sorts of annoying microphonics that occur with other cables when they move around or rub on your clothing. It’s nice to get one high-quality cable with a premium pair of IEMs, but to have three provided with the Pathfinder is a very nice inclusion indeed. The three 1-metre cables are terminated with 3.5mm single-ended, 2.5mm balanced and 4.4mm Pentaconn balanced jacks respectively, and attach the IEMs themselves via the familiar MMCX system used across all Campfire Audio IEMs. Full marks on the cable-front - bravo

Rounding out the accessory suite, a small IEM cleaning tool is provided, plus a whole big bunch of ear tips - three sets of foam tips, three wider-bore silicone tips, plus 5 x pairs of Final Audio’s E-Series silicone tips. No matter your ear size and shape, there’s bound to be a pair that fits and sounds right to you - I’ll go on to explain how each tip type affects the Pathfinder’s tuning shortly. 

Astell&Kern Pathfinder design and build

The new Pathfinder is reminiscent of the Solaris X in terms of its overall shape and profile, but that’s where the visual similarities end. Gone are the lairy red swirls and the ribbed patterns in the metallic body of the IEM shells - in their place we have a more streamlined, seamless finish to the “Night Sky” aluminium-bodied shells, and a six-sided trapezoidal stainless steel faceplate whose angular structure seems to be carrying-over Astell&Kern’s latest industrial design motif (which they call the “Mountain Peak”) that I recognise from their new Astell&Kern UW100 True Wireless Earphones which I had the pleasure of reviewing earlier this year. 

The Pathfinder is altogether much smaller than I was expecting, considering that it has no fewer than 5 drivers packed inside. With its svelte form-factor and smooth contouring, the Pathfinder makes for an exceptionally comfortable fit in my ears. The Pathfinder is held in place chiefly through the seal of their detachable tips, and while I’m wearing them no part of their body actually touches any part of my ear. 

The use of stainless steel carries over to the relatively thick bores of the protruding nozzle of each IEM, which are vented through seven smaller and one larger central hole. Because the nozzles are on the wider side, you may need to be careful when selecting aftermarket ear-tips, but you ought to be fine seeing as so many have been included with the Pathfinder. Astell&Kern and Campfire chose a “collaboration of Beryllium and Copper for the MMCX connections to ensure that they’re resilient and up to the task of having cables snapped in and out multiple times. 

Astell&Kern Pathfinder driver technology and interior design 

Astell&Kern explains that they went through several design iterations before landing on the Pathfinder’s final form, in their quest to achieve what they’re calling “Overwhelming Sound Performance” in their marketing materials. The complete redesign they undertook for the Pathfinder was done to achieve a) a wider frequency range, b) “realistic reproduction” and c) a “perfect balance”. 

The 10mm “Dual Custom Dynamic Drivers” have been implemented in a novel fashion with the two diaphragms facing one another (a bit like the cylinders in a boxer engine) and then vented towards the ear through a 3D-printed Acoustic Chamber. This chamber has been designed to allow the twin dynamic drivers to create bass in a more nimble fashion without creating the kind of over-exaggeration which can prevent the voicing of the Balanced Armature drivers from doing their “thing” in the mid-range. 

To achieve the level of mid-range performance that they were looking for, Astell&Kern and Campfire worked with Knowles to produce the world’s first “Dual Chamber” Balanced Armature driver. Compared to a “traditional” armature driver, this new Dual Chamber driver uses a single coil to drive two separate diaphragms in order to achieve a warmer, more natural-sounding mid-range. 

Complementing the twin dynamic drivers and the new Dual Chamber BA driver is a pair of newly-customised Dual Balanced Armature Drivers to deliver clearer and more precise treble notes thanks to their “Tuned Acoustic Expansion Chamber”, designed to retain detail in the highs while avoiding both shrillness and fatigue. 


At 6.2-ohms impedance and 94dB sensitivity, the new Pathfinder is a moderately sensitive IEM. While it doesn’t mean much by way of power to get it up to proper listening levels, its low impedance does mean that it’s best paired with a source with a suitably low (read: as close to zero as possible) output impedance to avoid anything fishy going on with its frequency response. The ideal source for the Pathfinder is, unsurprisingly one of Astell&Kern’s own portable players which are a spiritual match for any IEMs bearing their word-mark on the outside. First listening to the Pathfinder with the Astell&Kern A&futura SE200 Digital Audio Player via the 2.5mm balanced cable there is an ever-so-slight amount of noise floor in the form of background hiss, but as soon as I hit play on the Chili Pepper’s Blood Sugar Sex Magik it disappeared - and I only needed to turn up the volume wheel to 10/150 to get my feet tapping along to The Power of EqualitySwitching over to the 3.5mm single-ended cable there was no audible hiss whatsoever. 

So, how does the Pathfinder sound? In short, it’s probably the most straight-up enjoyable Campfire IEM I’ve listened to - it grabs you right out of the box with an addictive, balanced and musical tuning, and delivers refinement in spades irrespective of what genre you throw its way. Side by side with the Campfire Audio Solaris Limited Edition In-Ear Monitors, the Pathfinder simply feels more refined, more spacious, and has a more linear tuning that is easier to enjoy music with. 

A couple of bars into No Doubt’s Hella Good I realised that the Pathfinder has a solid foundation of super-satisfying and technically proficient bass. Those two low-end drivers work together in unison to provide a level of slam and visceral shove that only a dynamic driver can. It’s not the sort of overtly-pronounced bass that you’ll find in the Campfire Audio Vega 2020 In-Ear Earphones - instead, it’s accurate, well-extended and exceptionally taut. It’s definitely more sub-bass focused, and there’s no added emphasis above 100Hz that impedes or overshadows the Pathfinder’s mid-range performance. 

The Pathfinder’s treatment of mid-range frequencies is linear, natural and wonderfully clear. It’s tempting to say that the Pathfinder sounds mildly “V-shaped” at first due to its mild sub-bass lift and rather large soundstage (I say this when initially listening with the foam tips), but it has a way of presenting vocalists front-and-centre that gives it an extraordinary sense of presence. I was thinking just how well textured and intimate Beck’s lead vocal track in Paper Tiger sounded when I was suddenly struck by the grandiosity and width of the string section, which felt like it was coming from far beyond the confines of my head. The Pathfinder is one spacious-sounding IEM, and it layers and separates individual tracks in a distinct and enjoyable way. 

Another well-produced Beck track is Saw Lightning, and the Pathfinder was able to make the acoustic guitar in the left channel and slide guitar in the right channel feel like they were coming from an uncanny distance away from my head - their level of immersion really does need to be heard to be understood. 

Swapping ear-tips does change the frequency response of the Pathfinder quite noticeably. Switching over from the foam tips to the Final E-Series silicone tips adds noticeably more lower treble energy and makes vocalists and instruments take an extra step forward on stage, while the quantity of sub-bass is slightly subdued. Swapping to the wider-bore silicone emphasises these differences even further and makes the Pathfinder feel even more sparkly and almost “earbud”-like in character. For my tastes the foam tips are definitely the way to go - they make the Pathfinder a little more even though the transition from the mid-range to treble, and overall more enjoyable thanks to the better seal and subsequent lift in sub-bass. 

The Pathfinder’s upper octaves dance a neat line between delivering clarity and smoothness - there’s plenty of sparkle and energy in Toto’s Hold The Line, but the cymbal strikes and more energetic guitar solos never get strident nor offensive. Interestingly, swapping sources over from the SE200 to the Astell&Kern A&ultima SP2000T Digital Audio Player, the Pathfinder found a fair bit more shimmer and upper air extension, providing an overall more exciting and dazzling playback experience. With tube-mode engaged, the SP2000T offered a more restrained low-end performance, with sub-bass that was lower in quantity but more detailed and controlled. 

Final thoughts

I’m bloody glad that Astell&Kern and Campfire Audio decided to get the band back together to have another round at making a co-branded IEM, because the new Pathfinder has gone to number #1 with a bullet on my universal IEM list. It’s a good-looking, well-accessorised IEM package with some novel approaches to driver innovation and hybrid implementation, but it’s also gorgeously tuned in a way that favours both sheer enjoyment and technical prowess - the Pathfinder is a very easy IEM to like.

I highly recommend that you cue up a few test tracks, take the time to drop into your local Addicted To Audio store, and enjoy listening to the fruits of this collaboration for yourself. 

Astell&kernCampfire audioIn-ear earphones