THIEAUDIO Cypher Review: The HD600 Spirit for the Modern Era
Jin Soh
THIEAUDIO is a name synonymous with Chi-Fi audio, with the Monarch and Oracle in-ear monitor series serving as reliable mainstays in the industry for years. What fewer people know is that the brand has several headphone releases under their belt as well, one of which we’ve had the pleasure of reviewing before.
Now, THIEAUDIO is adding another chapter to that story with the Cypher, an open-back headphone currently on Kickstarter with an early bird price of 329 USD (compared to its 399USD retail price). The lovely folks over at Linsoul sent us an early production unit of the Cypher for review.
What Is It?
The Cypher is an open-back headphone built around a newly developed 50mm dynamic driver by THIEAUDIO. Inside that driver sits a 20-core N45 magnetic array paired with a semi-crystalline polymer-rubber composite diaphragm. The brand claims a reference tuning, promising powerful yet controlled bass alongside neutral mids and treble. We’ll get to whether that holds up in a moment.
The Cypher itself is rather hefty and cool to the touch from the nearly all-metal construction. The ear cups are CNC machined from aerospace-grade aluminium and feature a vintage speaker-inspired grille design that draws comparisons to some of Hifiman’s planar-magnetic offerings and even a few Audeze models. It’s a handsome look that carries a sense of audio seriousness that just whispers ‘hi-fi’. The headband is constructed from a carbon fibre and stainless steel alloy, while the suspended headband lining is wrapped in genuine Coby lambskin. It’s already looking like a clear step up from THIEAUDIO’s more affordable headphone releases so far.
The ear pads are made from memory foam velour and attach magnetically, making them easy to swap out. Additional pairs are available as add-ons on the Kickstarter page, though whether THIEAUDIO or their distributor Linsoul will offer pads in different materials down the line remains to be seen. The earcups themselves swivel and the mechanism feels almost stiff at first, but that tightness works in its favour by keeping the cups secure and flat against your head rather than flopping around.
In the box, you also get a braided copper cable with 3.5mm connectors on the headphone end and a 3.5mm plug at the other, along with a 6.3mm quarter-inch adapter. And then there’s the case, which definitely deserves a special mention.
It is genuinely unlike anything I’ve seen shipped with a pair of headphones, resembling a vintage, fashionable ladies’ purse more than an audio storage accessory. Whether that is charming or confusing will depend on the person, but it certainly leaves an impression.
At 32 ohms, the Cypher is easy enough to drive directly from a laptop or phone headphone jack, though as we’ll get into, it does open up with a proper source behind it.
How Does It Sound?
THIEAUDIO’s claim of reference tuning is pretty much on the mark. The Cypher leans toward studio neutral with a slight hint of warmth underneath, and a treble that rolls off earlier than you might expect from an open-back design. It’s not the kind of headphone that announces itself with dramatic flair. It is measured, deliberate, and asks you to meet it on its own terms.
The soundstage, as befitting an open-back, is generous in both width and depth. Instruments are easy to place and the overall image is spacious, though the shape of the stage is a touch blurry and undefined at its edges rather than precise.
With an impedance of 32 ohms and sensitivity of 96 dB/mW, the Cypher isn’t too difficult to drive at all. Through dongles like the iBasso DC03Pro and the Snowsky Retro Nano, I only had to raise the volume less than 5 notches up from my usual listening gain with more sensitive IEMs. On more powerful sources like the iBasso DX170 on high gain mode, the Cypher opens up more in terms of soundstage and detail.
Bass
Starting with the bass, mid-bass takes more of a leading role here than sub-bass, with the latter offering minimal presence and limited extension. The bass as a whole is not particularly tight, landing more as a wide, rounded slap than a solid, focused thump. It is also not especially fast or deep, and the low-end is a tad ‘bloomy’ or veiled as a whole.
For genres like pop and R&B, the impact is sufficient and never offensive, but it is restrained enough that calling it fun would be a stretch. That restraint, however, is precisely what makes it work as a monitoring headphone.
Mids
The midrange is where the Cypher really shines. Vocals sit front and centre with good placement within the soundstage, almost as if other components within the soundstage are shifted aside, making way for it.
That being said, vocal presentation feels a tad distant rather than close and intimate. Male vocals carry a natural timbre, sitting comfortably in the mix without sounding pushed or artificial. Female vocals are naturally rendered with a touch of warmth that adds a subtle silkiness, though they stop short of being breathy or what some might describe as ‘sweet’. It is a largely uncoloured presentation that stays out of its own way, which is both a good and a bad thing depending on your preference.
Highs
Treble is quite a contentious part of the Cypher’s character. It rolls off noticeably, which holds back the crispness and air you might associate with a well-tuned open-back. The result is something like knowing exactly where an instrument sits in the soundstage but perceiving it through a slight veil. You hear the cymbal hit at two o’clock, you can place it clearly, but that crisp shimmer is softened before it fully lands.
This does mean the Cypher is never bright or fatiguing, which will be a genuine relief for those who have grown weary of sharp, peaky treble, but it comes at the cost of resolution and edge definition.
Is It Worth It?
If you have spent enough time with loud, bassy, or exaggerated headphones and are ready for something more considered, the THIEAUDIO Cypher offers exactly that. I’d call it a more mature take on audio, trading excitement for accuracy and longevity. For sound mixing and monitoring work, it also makes a compelling case for itself, with a presentation that is honest without being too clinical or cold.
At an early bird price of 329 USD on Kickstarter, the Cypher is competitive for what it offers in terms of build quality and tuning philosophy. Just go in knowing this is a headphone that rewards patience and attentive listening rather than one that grabs you by the collar from the first track.
Do note that the THIEAUDIO Cypher Kickstarter will end on 22 March 2026 so back the product here if it sounds like your kind of thing. You can also add on extra ear pads for future proofing and a choice of several 4.4mm cables for pairing with balanced sources.