Golden Ears: Thieaudio Monarch MKII Review

Thieaudio has been a recurring brand for us at, often delivering exceptional value for the money. That same thing is true with the product we’re reviewing in this article, but it exists in a whole different class. Today, we’re looking at the Thieaudio Monarch Mk II, a world-class IEM that retails for $999. That’s a lot of money for an IEM, so let’s take a look and see how well it earns its keep. What’s in a thousand-dollar earphone, anyway?


  • Current Price: $999 (Linsoul
  • Model: Monarch MKII
  • Drivers: 
    • 10mm Dynamic Driver
    • Sonion / Knowless Balanced Armatures Driver
    • Sonion Electrostatic Driver
  • Connector: 0.78mm 2-pin
  • Cable: 26AWG OCC silver plated cable with fabric-coated
  • Cable Length: 1.2 meters
  • Plug Type: Smart-switch (2.5mm,3.5mm,4.4mm)
  • Impedance: 36 ohm
  • Sensitivity: 108db
  • Nozzle Size(stem): 5.4mm
  • Nozzle Size (lip): 6mm

What is Golden Ears?

Welcome back to Golden Ears! This is our semi-regular review column dedicated to exploring the world of high-end audio. As a site that’s covered consumer audio for several years, we sometimes get the opportunity to check out very high-end gear. If you’re anything like us, you’ve wondered why anyone would pay $500 or even $1000 more for a headphone or earphone. This column explores exactly that to show you what these upper-crust products offer and whether it’s really all about hype and marketing.

Before we begin, a few things to keep in mind, cribbed from my review of the Mangird XENNS Up:

  • Forget what you know about value. When you enter the world of high-end audio, that gets turned on its head. Once you step into the world of HiFi, it’s not at all uncommon to see top-of-the-line headphones go for several thousand dollars. Here’s a list of over-ear headphones that feature electrostatic drivers like the earphone we’re looking at today. $410 to $6200. This is an expensive hobby steeped in chasing incremental improvements that usually cost more the higher up the chain you go. 

  • Yes, you can hear a difference. Despite how great your favorite pair of Sony’s of Bose headphones sound, there’s always room to grow and, yes, you can absolutely hear a difference. No, you don’t need to be an audiophile to hear it. Yes, placebo effect is absolutely a thing. But no, that’s not a reason to dismiss an earphone without hearing it for yourself. 

  • Craftsmanship costs. As you’ll see with this earphone, it’s not all about the sound. When you step up to these expensive earphones and headphones, you’re paying for the technology inside it and the craftsmanship on the outside. Hand-painted shells. Unique designs. One-of-a-kind finishes. These are all factored into the price.

  • It’s not all about price. Just because a headphone is expensive doesn’t mean it’s good. Just because a headphone is cheap doesn’t mean it’s bad. If you can only afford $100 on one headphone, there are plenty of amazing options that can also sound great. High-end listening is very much a game of nuance and personal taste. 

With that out of the way, let’s dig into the Thieaudio Monarch MKIIs!

Thieaudio Monarch MKII – First Impressions and Key Features 

The Thieaudio Monarch MKIIs are the successors to the original Monarchs which were released in mid-2020. Those earphones were very well regarded in the audiophile world and, like most of Thieaudio’s catalog, were seen as a great value for the money. They weren’t without their criticisms, however, as some users found them to be somewhat sharp and the bass over-emphasized. In general, however, they were well received by the community.

The Monarch MKIIs are out to address those concerns while also building on its strengths.They feature the same tribrid driver configuration of the original: 1 dynamic driver for the bass, 6 balanced armatures for the mids, and 2 electrostatic drivers for the highs. There is, of course, some crossover here, and, in fact, Thieaudio has changed how these drivers operate across the frequency spectrum. They break down as follows: 

  • 10mm Dynamic Driver and (2) Sonion Balanced Armatures: Sub-bass and bass response, allowing the low-end to transition seamlessly into the mids and enhancing clarity and detail.
  • (4) Sonion Balanced Armatures: Mid-frequency response
  • (2) Sonion Electrostatic Drivers: Treble, air, and atmosphere

These are all premium components, designed for impeccable high-resolution audio in the original Monarch and then redesigned to improve that performance further with the MKII.

The combination of these components is intended to provide a balanced, incredibly detailed sound signature. It’s a success on that front. Thieaudio pitches these as being excellent studio monitors and I can see it. Based on the reports of the original Monarch, these have tamed the base and brought the highs in line with the rest of the frequency spectrum. 

The internals aren’t the only aspect to have undergone a redesign either. The aesthetic of the headphone has been completely reinvented and is, in my opinion, now one of the coolest looking you can buy today. The earphones feature resin shells in a traditional UIEM shape and faceplates of hot magma. It’s absolutely striking and I absolutely love it. 

The cable that comes with the earphones has also been upgraded with Thieaudio’s new Smart Cable. It’s braided in paracord instead of plastic and features a new interchangeable end system. Out of the box, it supports 3.5mm single-ended, 2.5mm balanced, and 4.4mm balanced terminations. The last cable required linking together adapters which quickly became unwieldy. This is a much better solution. It feels very nice in the hand but is slightly heavy and does transfer minor microphonics. I wish Thieaudio offered this same cable without the paracord, but it works and is overall very nice. 


Also included in the box are a set of silicone and memory foam tips. Along with this is a nice zippered storage case. At this price, I would have liked to see more accessories, but it seems clear that Thieaudio wants you to use memory foam tips and this is one way to encourage that. Still, as a fan of silicone, I would have appreciated some different shapes or bore widths.

Thieaudio Monarch MKII – Fit and Comfort

The Thieaudio Monarch MKII has a lot going on (and going for it), but packing all of those drivers into a single IEM has a definite impact on size. While I didn’t find them uncomfortable, they are definitely on the larger side for what I can reasonably wear with small-to-medium-sized ears. They do protrude a bit, too, and are slightly heavier than many simpler IEMs. This is also impacted by the braided cable which has more weight and drag than typical, plastic-coated wires. The combination makes them a poor fit for active use — but then, do you use incredibly expensive audio equipment for working out? I know I don’t and wouldn’t expect many people would, so that’s less of an issue here than it would be elsewhere.


With stationary or light active (walking) use in mind, the Monarch MKIIs are comfortable to wear. Thieaudio is very good at developing earphones which can be worn over long stretches and these are no exception. More than once, I wore them for upwards of three hours without any soreness or fatigue. If you have small ears, this may not be the case, but for anyone medium-sized and up, they should be good for extended listening. 

Thieaudio Monarch MKII – Listening Impressions 

My testing of the Monarch MKII was performed using an Xduoo XD-05 Plus. It offers a total 1000mW of amplitude and a great DAC, allowing these IEMs to be pushed to their full potential. You won’t need such high levels of power, of course, but you should plan on amping these earphones somehow.  A standard dongle DAC will get them plenty loud, but to perform their best, they need more juice than most can provide. Most dedicated DAC/amp setups will do, but for users on a budget and with portability in mind, I recommend the TempoTec Sonata HD Pro. If you have a little more wiggle room, the iFi Hip-Dac 2 is a great choice that will provide more than enough headroom.

It’s also important to note that I was not able to listen to the original Thieaudio Monarch ahead of this review. I’m familiar with tribrids, however, and consider Thieaudio’s Oracle and the Mangird XENNS Up to be among my favorite (and most listened to) IEMs. 



The first thing that stood out to me about these IEMs is their bass performance. The sub-bass reaches deep and has outstanding depth. There is an almost subwoofer-like effect to these earphones that tricks your mind into thinking you can feel the bass, even though it’s only within your ear canal. It’s really pretty tremendous and is immediately impressive compared against the Oracle and XENNS Up — though to a lesser degree with the latter — the bass on the XENNS is also great but doesn’t have the same reach as the Monarch Mk IIs. From what I understand, the sub-bass amount has been reduced compared to the original Monarch but that its quality has been improved.

The mid-bass (bass you hear versus feel) is tight and detailed. Pearl of the Stars by Coheed and Cambria had incredible texture in the synths that, when paired with the sub-bass rumble, felt downright ominous. Church by Tom MacDonald and My Stress by NF offered the kind of thump and slam that brings those tracks to life. Shifting to classic rock, the kick drums on Love in an Elevator by Aerosmith were punchy and realistic to the live shows I’ve been to over the years. 

This is some of the best bass I’ve heard. Ascending the Golden Ears ladder, perhaps that would change once we tip to more than $1000, and from what I’ve heard from other users, that may indeed be the case. What I can say is that below $1000 this is excellent performance across multiple genres and even into movies and video games.


Image Credit: In-Ear Fidelity


The mid-range on this set is exquisite and absolutely rich in details. The Monarch MKII is very natural sounding and lacks any harshness in vocals or instruments. Electric guitars sound almost liquid. Violins and cellos have realistic timbre and sweetness, particularly in melancholy tracks that already tug at your emotions. Vocals and instruments have engaging attack and realistic decay.

But this set is really about what’s happening within. It’s the fine details that often get lost. As instruments layer on top of one another, it’s easy to miss out on the intricacies that you would hear in real life: the washy, swirly movement of a particle verb, the nuance of a bow drawn across a string, and the swell as the musician transitions into a wider arm movement, the decay trails of a stereo delay panning from right to left — and above all, the texture that lays on top. 

Describing sound is a matter of analogy. So, let me put it like this. Imagine a metal block. The surface can be mirrored, matte, sandblasted, or brushed. Each of those will look different to the eye and feel different under your fingers. That’s what sound texture is like, and the Monarch MKII leaves no question about exactly what you’re hearing. This is UHD for your ears. 


Like the mid-range, the treble is well-extended and tuned. The MKIIs have plenty of air and shimmer, tuned to push forward a bit and showcase that extra bit of detail. Despite the humps at 4kHz, 8kHz, and ∼16kHz, there is no sibilance or sharpness to the treble response. The ESTs handling the upper-range are very well tuned to present the highs realistically and to enhance the sense of atmosphere and space in the music.


The soundstage on the Monarchs isn’t congested but it’s not particularly spacey either. It falls somewhere in the middle. You won’t hear a knock in a song and find yourself looking toward the door, for example. That said, it’s spacious enough to be very enjoyable. It offers enough breathing room to make for a pleasant listen, which is most important, but it won’t blow you away with its sense of width or depth.

Imaging is excellent. Instruments have a defined position within its soundstage. Walk This Way by Aerosmith sounds almost as if you’re in the center of a stage with the band surrounding you. The way in which the earphones pull apart the layers and reveal the detail within is also helpful in creating its globe of sound. 

Overall Impressions

The Thieaudio Monarch MKIIs are the more premium, audiophile-grade IEMs I’ve had the pleasure to use — and a pleasure it was. These headphones are incredibly impressive. The target audience for a $999 earphone is going to be narrow, but I genuinely believe most users will find a lot to love here. This impression has been reinforced by other users who have used a wider selection of even higher-end earphones than this. Crinacle of In-Ear Fidelity is one of the most respected (and breezily critical) reviewers in the business and has the most extensive ranking list and graph database in existence today. He has put them at the absolute top of his list. That by itself says quite a bit, but it’s reinforced by the fine folks at who liked it much more than the original Monarch. AntDroid over at AudioDiscourse had equally positive impressions from his time with them.


Final Thoughts

At $999, these earphones are expensive and exquisite. From looks to sound, they’re incredibly impressive and a lot of fun to listen to. If you have the opportunity, I encourage you to try them for yourself. If this is what Thieaudio’s top-tier looks like, I can only hope we get more in to trial. It really is as good as the hype has made it out to be. Find out more over at Linsoul!


The product described in this article was provided by the manufacturer for evaluation purposes. Golden Ears: Thieaudio Monarch MKII Review

Fry Electronics Team

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