The Ranking of Kings: Thieaudio Monarch MkII and MkIII Comparative Review 2024

Introduction

When people think about high-end in-ear monitors (IEMs), Thieaudio usually comes to mind. They may be famous now, but that wasn’t always the case. Their breakthrough came three years ago with the publication of Thieaudio Clairvoyance and Monarch. Their reputation as a serious player in the IEM scene was firmly established by the Monarch.

And if the first is fantastic, then the sequel must be even better, isn’t it? Because of this, I am bringing along not only the Monarch MkII but also the brand new Monarch MkIII today. I have now had the opportunity to assess the Mark II, even though it has been out for more than a year. Come with me as I examine the $1,000 IEMs side by side and in the context of the fiercely competitive kilobuck market today.

What’s in the Box?

There is almost any difference between the MkII and MkIII in terms of packaging. Both provide you with:

S/M/L silicon tips in a generic set.
Foam tips in sizes S, M, and L.
A little microfiber cleaning cloth with the Thieaudio logo in black.
A big bag with a zipper.
Connectors can be switched out for 2.5/3.5/4.4 mm plugs on this 4-core braided 2-pin cable.
The IEMs themselves—made of sleek black resin with a variety of attractive faceplate options.

The stock cable is the deciding factor in each. The brown cable used in the MkII is thicker and braided with cloth, but the beige cable used in the MkIII is thinner. Because of its finer texture and reduced cable memory, I favor the MkIII’s. Additionally, the MkIII’s replaceable jack is significantly smaller and more elegant than its large MkII counterpart. It may sound insane, but kudos to Thieaudio for bundling high-quality cables with $1,000+ equipment. How many businesses fall short at this stage is surprising.https://headphonis.com/s.

The Monarch MkIII’s modifiable faceplate is one of its many appealing features. You can choose from more than twenty-one unique styles, but it will cost you an additional $100. Gorgeous, isn’t it? I have the “butterfly” pattern. The MkIII includes an extra dynamic driver for driver configuration, allowing for a final set-up of 2 DD + 6 BA + 2 EST.

The shell was redesigned to accommodate the additional driver, resulting in a significantly bigger shell for the MkIII compared to the MkII. But I thought they were roughly the same size in terms of fit. With a nozzle diameter greater than 6 mm, these IEMs aren’t the most comfortable I’ve ever worn, but other than that, I don’t have any major complaints.

Note for Newbies: DD stands for Dynamic Driver. BA stands for Balanced Armature. It stands for electrostatic. A variety of driver technologies are employed in IEMs to generate the final audio output. Despite their differences, the number and type of drivers in an IEM are less critical. How things sound is what matters.

Sound

The tuning of both IEMs is excellent. While the MkII boasts a perfectly balanced profile, the MkIII’s midbass prominence and upper treble exaggeration give it a slightly U-shaped signature. The MkII is a very fine, almost flawless, and “normal” sounding in-ear monitor (IEM), in my opinion. Contrarily, the MkIII takes a few features from the MkII and turns them up to a whole new level. Though I do believe it fails to fully appreciate the big picture, it does bring several novel features that set it apart from the MkII and finally win me over. In general, I consider the MkIII to be more of a modest upgrade and a sidegrade.

Thieaudio Monarch MkII (blue) and MkIII (red) frequency responses. A clone microphone of the IEC-711 was used for the measurement. Only measurements taken by this particular microphone can be used for comparison. It is possible that the peak around 8–10 kHz is just a measuring artifact and that the actual peak does not exist at all. Any readings over 8 kHz are wildly inaccurate. Make use of several measures if at all feasible.

Bass

What makes the MkIII bass so intriguing is its low end. As soon as it starts working, you’ll feel the bass energy “fill-the-room” and keep it going for as long as you need it to. But in the middle of all that, there’s a big midbass body that can handle any note that hits it. This “two-tier” method worked well for me. The midbass is responsible for controlling notes, adding weight, and defining and texturizing the sound. On top of that, the notes are emphasized by the constant bass energy that surrounds it. But I wouldn’t say the MkIII’s fleeting reaction is spotless. Its midbass body’s richness completes the fleeting qualities.

When going from the MkIII to the MkII, the lack of bass is immediately noticeable. The MkII is a noticeably thinner IEM than the MkIII, even though their measurements are rather close in the graph above. The bass of the Thieaudio MkII was fine-tuned with meticulous attention to detail. It has been meticulously measured in every respect.

You won’t notice a thing because the bass shelf blends into the lower mids like clockwork. Similar to the MkIII, the MkII doesn’t have the sharpest transients, but the notes are slightly cleaner because there is less midbass. The decline of notes is precisely long enough to catch all of the tones’ tails. There’s no boominess or oomph to it. Contrarily, I thought it had slightly less texture than the MkIII’s.

The Mark III is my favorite of the two. When listening to old favorites, the MkIII’s pronounced midbass body brings a new level of musicality. In terms of presentation, they’re practically interchangeable. They don’t feature any particular instruments, yet they sound far more refined and mature than the one-dimensional offers from cheaper alternatives. The bass’s dramatic impact is their sole flaw. There isn’t enough of a bang for me to pay attention.

Mids

The MkIII boasts a more robust midrange, in contrast to the MkII’s clean, balanced tone. Because of this, playing stringed instruments, such as acoustic guitars, becomes somewhat of a personal affair. Regarding instrumentation, the MkIII offers excellent midrange resolution. The MkIII takes the already excellent MkII and makes it even better by showcasing electric guitar riffs or delicately plucked strings interspersed throughout the song.

The MkIII’s male and female vocals are well-balanced. The warm midrange is ideal for male vocals, while the slightly forward upper midrange is reserved for female vocals. In order to highlight their own qualities, they slightly deviate in tone from one another. This stands up more clearly on songs that feature male and female vocalists. When it comes to vocalists, the MkII doesn’t discriminate; both do a great job. This little coloring of sound is another reason why I like the MkIII. A slight sibilance is there, but it was never a problem for me.

Treble

The Monarch Mk II’s treble is just delightful. In terms of the finely balanced game of treble presence/brilliance, evenness, and timbre, I have not heard better treble from an IEM. In my experience, the majority of IEMs only allow you to choose two options out of three. All three are captured by the MkII. It doesn’t sound uneven or peaky because of the superb control over the lower, mid, and upper treble.

Its treble brilliance allows the top harmonics to shine without being too pronounced or disrupting the overall tone balance. The whole thing is encased in an amiable tone that isn’t harsh or excessively sharp. This treble is so wonderful because it isn’t overbearing, which is something you won’t notice at first.

In contrast, the treble of the Mk III expands upon and transcends the foundation of the Mk II. The addition of additional treble zing is to blame. An upper treble peak has emerged, destabilizing the equilibrium that the MkII painstakingly achieved. That it’s overly luminous or peaky isn’t the main issue. In contrast, it brazenly resolves each shimmer and sizzle of the hats and cymbals, making you feel like you’re standing right there with the percussion as the sticks slam into them.

Due to its exaggeration, I find this level of detail to be somewhat strange. I can understand why the MkIII would be accused by those who criticize bright headphones and IEMs for having “fake treble detail”; nevertheless, I do not quite agree with that assertion.

In contrast, the treble of the Mk III expands upon and transcends the foundation of the Mk II. The addition of additional treble zing is to blame. An upper treble peak has emerged, destabilizing the equilibrium that the MkII painstakingly achieved. That it’s overly luminous or peaky isn’t the main issue. In contrast, it brazenly resolves each shimmer and sizzle of the hats and cymbals, making you feel like you’re standing right there with the percussion as the sticks slam into them.

Due to its exaggeration, I find this level of detail to be somewhat strange. I can understand why the MkIII would be accused by those who criticize bright headphones and IEMs for having “fake treble detail”; nevertheless, I do not quite agree with that assertion.

I wouldn’t go so far as to claim that the MkIII is destroyed by this higher treble boost, though. Its output is still remarkably controlled, and its treble is excellent. Just a heavier hand compared to the Mk II. Additionally, it is only heard on tracks that incorporate percussion instruments like as hats and cymbals; it is not present on all tracks.

This upper treble was just fine for pop and other genres that heavily use synths and samples. Because of the MkIII’s superior layer resolution and vibrancy, I can understand why some listeners would choose it. This treble is perhaps also responsible for the dazzling quality of female voices. In terms of treble, I like the MkII over the MkIII, which has a 60/40 split. In comparison to the other 90% of IEMs, I would gladly choose it.

Presentation

Easy imaging and stacking are two of the many benefits of the MkII’s wide horizontal field of view. The soundstage is spacious and the instruments are neatly arranged. I won’t hold that against the MkII because nothing feels cramped in any manner, even though it doesn’t have much depth or height. The stage width is further expanded by the MkIII. The very edges of peripheral instruments are sharply delineated. On the other hand, the imaging is somewhat W-shaped, with a more intimate core image and more stretched peripheries. Compared to the more scattered sound of the MkII, this kind of imaging seems less natural.

I’ve mentioned this before in passing, but the MkIII offers outstanding detail retrieval for ambient instruments. Midrange resolution is top-notch, and the somewhat unrealistic treble performance is a contributing factor. The midrange of the MkII is similarly detailed, although it falls short of the degree achieved by the MkIII. When it comes to background music that features complementing notes, I’m on the verge of saying that the MkIII is one of the most resolving IEMs I’ve ever heard.

Comparisons

Symphonium Helios

Among the best in-ear monitors (IEMs) priced at around $1,000, the Symphonium Helios is a top pick. It’s a great example of how to achieve professional-level intonation and technical proficiency without wasting time. To a large extent, the MkII is like a milder Helios, in my opinion. The Helios’s all-BA configuration results in finer transients and a more focused bass response. On the other hand, it aims for a neutral + subbass tuning instead of the MkII’s balanced profile, which makes the sound a little drier.

Fantastic treble is present in both IEMs. On the other hand, the Helios has a somewhat more upfront and crisper sound—almost crystalline—than the other. Thanks to its extra brilliance, the Helios is my favorite. Although both have similar staging and resolution, the Helios triumphs due to its superior understanding of dynamics.

Since the MkII is essentially a milder Helios, it is easy to draw parallels to the MkIII. Specifically, the MkIII’s midbass body gives the Helios the warmth it lacked and stands in sharp contrast to its lowered lower mids. While the Helios’s treble is noticeably more prominent, the MkIII’s superior overall resolution more than makes up for it.

64 Audio U4s

Our top pick for a kilobuck in-ear monitor is the 64 Audio U4s. It chooses a lively bassline sound without compromising on tonal consistency. Consequently, it falls short when compared to the meticulously calibrated MkII. When compared to the U4s, the MkIII is more in line with spirit while yet being better tuned. I would say that the U4s has a thick midrange, the MkIII has a little warmer sound, and the MkII has a clear sound.

The U4s make it sound so much better by adding a fuller tone and more dynamic range. Indeed, that is the unique selling point of the U4s. The U4s are a great recommendation for anyone trying to get into the game because of their enjoyable and easy-going nature, even though they don’t outperform the MkIII in resolving ability or the MkII in treble performance.

Should You Buy Them?

Yes. In particular, I can speak well of the Thieaudio Monarch Mark II and Mark III. Since Precogvision and I were trying to be as specific as possible in our suggestions, we opted to leave the Monarch MkII out of the buying guide. As impressive as the Helios and U4s were, the MkII seemed a bit too “ordinary” in comparison. Maybe we were a little too quick to make that call, looking back. When it comes to IEMs, the MkII is still a great and secure choice. Everything that an excellent IEM should perform is exemplified by it.

That being said, I find the MkIII to be more appealing than the MkII. Character is there. The more time spent on a hobby like this, the more likely it is that one will want something more distinctive. The MkIII does this with a midbass body and treble performance that is on level with or better than its predecessors, and it backs all of that up with technical execution.

When presented with the choice between the MkII and the MkIII, I find myself gravitating toward the MkIII. Among the greatest options about $1,000 (and, to be honest, even beyond), it is proudly ranked by me among the Symphonium Helios and 64 Audio U4s. Never before has the kilobuck market been in such good shape.

Appendix

Here are the Thieaudio Monarch MkIII’s dimensions according to the standard industry standard, the B&K 5128:

Opposite the MkIII are the red and blue colors. The present objective, taking into account the diffuse field (DF) and an 8 dB sloping downwards, is black. In case you’re interested, here’s a video of Resolve discussing it on The Headphone Show.

In order to compare it to other IEMs I’ve measured, I utilized my own clone 711 data for this assessment. That information isn’t up to snuff with these measurements, but as we delve deeper into the B&K 5128 data, most readers will recognize it.