A pair of Campfire Audio IEMs will always try to grab your attention before you’ve even heard them, but the Alien Brain have plenty of the substance required to back up the style. The smaller-eared among us may find them rather too much of a good thing, though…

• Agile, expressive and confident sound
• Typical Campfire Audio commitment to bonkers design

• Sound is even more fit-dependent than is usual
• Not without very capable competition
• Typical Campfire Audio commitment to bonkers design

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• Hybrid five-driver layout

• Balanced and unbalanced cable terminations

If the look, the specification and the name of a pair of wired in-ear monitors is slightly unusual and slightly confusing, then the odds on it being a Campfire Audio pair of wired in-ear monitors are short.

Take the Alien Brain, for instance: it seems safe to say £999 ought to buy some premium audio performance, but when it’s being spent with Campfire Audio it’s certain to buy more besides…

• Three types of ear-tips in three different sizes
• Light and comfortable fit
• IEM dome covers that look a bit like an alien brain

You’d be disappointed, wouldn’t you, if a pair of IEMs called Alien Brain looked ordinary and unremarkable? Yes, these are identifiably in-ear headphones – but Campfire Audio is never knowingly understated where design is concerned.

So yes, the earbuds are very carefully ergonomic in shape, with a black PVD stainless outer shell and blue PVD aluminum accents at the MMCX capture-and-fasten rings where the earbuds connect to the cable.

Yes, the standard of build and finish is everything this lofty asking price demands. But it’s the iridescent dome lid that offers a glimpse of the components beneath while seeming to glow a gentle blue colour that really sets these IEMs apart – because it’s contoured and textured to be suggestive of something H.R. Giger might have created for Ridley Scott’s 1979 sci-fi classic.   

The Alien Brain come with three types of ear-tips (silicone, foam and High and Clear silicone), each in three different sizes. They come with a fairly compact leather case in Solar yellow, as well as a tiny two-pocket pouch. A cleaning tool and the customary ‘CA’ lapel pin badge complete the package.

• Five-driver hybrid design
• Balanced and unbalanced cable options

Inside each IEM, vaguely visible through the Alien Brain dome cover, is a five-driver layout that is, according to Campfire Audio, capable of a frequency response of 5Hz – 20kHz.

A 10mm glass-PU dual-magnet dynamic driver takes care of the lower frequencies, while a couple of balanced armatures deal with the midrange and another two take care of the high end. This model is just the latest example of Campfire Audio’s established taste for this kind of hybrid driver design.

The Alien Brain are supplied with two lengths of ribbon-style cable for connection to the IEMs at one end and a source of music at the other. Naturally, one cable has an unbalanced 3.5mm termination and the other has a 4.4mm balanced pole – and equally naturally, Campfire Audio calls these cables Time Stream.

There’s also a very useful little dongle DAC in the packaging. At one end there’s a USB-C plug attached to the DAC block, and at the other (attached to a length of braided cable the same colour as the Time Stream stuff) there’s a 3.5mm input.

A native resolution of 32-bit/384kHz and DSD256 capability make this, on paper at least, a match for stand-alone products costing three figures.  

• Dynamic and carefully organised presentation
• Correct fit is even more critical than is the norm with IEMs

The beauty of the way the Campfire Audio Alien Brain are configured is that extremely high-quality sound is available even if your source of music is nothing special.

Sure, these expensive in-ear monitors sound their best when attached to an equally capable (and, inevitably, equally pricey) digital audio player or something like that – but plug that USB-C dongle DAC into the data transfer port of a bog-standard smartphone and plug in the 3.5mm unbalanced cable, and magic happens. Your smartphone becomes an entirely valid digital audio source.

It’s with the 4.4mm balanced cable connected to a FiiO digital audio player and a DSD64 file of the 2025 MFSL remaster of Michael Jackson’s Off the Wallplaying that the Alien Brain really sound like the asking price, though.

They’re an energetic, agile and eloquent listen at every turn, able to reveal the drive and attack the material embodies without ever losing the run of themselves. Detail levels are high at every point, and the amount of insight that’s available into the mechanics of Quincy Jones’ masterful production is intermittently thrilling.

Tonally these headphones are fractionally on the chilly side of neutral, but they’re winningly naturalistic when it comes to texture and timbre – the blare of the brass section, the rasp and the constant harmonic variation, is utterly convincing.

The top of the frequency range is substantial enough to counteract the ample bite and crunch – or, at least, to balance it out a little. The midrange shoots for a similar neutrality, which allows the character and flavour of a voice to come across nicely – and just as readily as the information regarding technique and tone.

Soundstaging is straightforwardly impressive, too. These are in-ear monitors, of course, which means that everything happening gives every impression of happening inside your head – but the Alien Brain nonetheless create space and lay out a stage that sounds quite a lot wider and more open than is the established IEM norm.    

Frequency response is nicely even from the bright and fulminating high frequencies to the rapid, articulate bottom end. But it’s at the bottom of the frequency range that the Campfire Audio reveal the only idiosyncrasies that don’t concern their appearance.

There’s no shortage of authority or eloquence to the bass response, and the attack and decay of individual sounds are controlled to such an extent that rhythmic expression is never in doubt. But the Alien Brain are extremely dependent on the physical fit you’ve achieved, and if that fit is anything less than absolutely perfect then the low end can sound undernourished and short of substance.

Of course, this is the case with any pair of IEMs you care to mention, but with these Campfire Audio it’s somehow more so. They’re relatively large earbuds, which makes getting that ideal fit a little trickier than it would be with any number of price-comparable rivals – and unless you get the fit just so, the Alien Brain can sound a little lightweight and lacking in outright impact. 

Should you buy it?

I am straightforwardly grateful a) that Campfire Audio exists, and b) that Campfire Audio’s unique approach to design and, to a lesser extent, marketing seems to be working.

Are the Alien Brain absolutely the best IEMs out there for £1K or so? Probably not. Are they a great-sounding pair of in-ear headphones that have a bit of character as well as plenty of performance? I think you know the answer to that…

I connect the Campfire Audio Alien Brain to a FiiO M15S digital audio player using the 4.4mm balanced cable.
 
I also connect to the same device using the USB-C dongle DAC and the 3.5mm unbalanced cable in order to assess the FiiO’s built-in DAC against the Campfire Audio alternative.
 
I also connect via the dongle DAC to an Apple iPhone 15 Pro, and to an Apple MacBook Pro using the 3.5mm unbalanced cable and the dongle DAC into one of its USB-C slots. This way I’m able to listen to lots of different types of content, of many different digital audio file types and resolutions.

• Tested with real world use
• Tested for several days

	Campfire Audio Alien Brain Review
Manufacturer	Campfire Audio
IP rating	No
Release Date	2026
Driver (s)	10mm Glass-PU dual-magnet dynamic; 4 x balanced armature
Connectivity	3.5mm unbalanced; 4.4mm balanced
Colours	Black
Frequency Range	5 20000 – Hz
Headphone Type	In-ear
UK RRP	£999
USA RRP	$999
EU RRP	€1199
CA RRP	CA$1399
AUD RRP	AU$1799