Theaudio Monarch MKII Review – The Most Stunning, Powerful & Awesome Earphones?

The Thieaudio Monarch MkII has taken so much of what made the original Monarch earphones a smashing success and built on it. This review breaks down how Thieaudio met expectations with this hotly anticipated release and how they went above and beyond—possibly creating the best earphone on the market.

The Monarch MKII is a monitor-style audiophile earphone with a tribrid driver configuration. It uses a combination of dynamic drivers, balanced armatures, and Electrostatics to create the sound. All this technology is in a gorgeous new body, and they throw in some innovation with the accessories as well. Please read the rest of our in-depth review to find out the reasons we decided that this is our best earphone of the year for 2021.

Where to Buy the Thieaudio Monarch MKII?

Lead review image of the Thieaudio Monarch MKII IEM
The Thieaudio Monarch MKII is one of the most beautiful earphones we have ever reviewed at AudiophileON.

Right now, the Thieaudio Monarch MKII is available for purchase directly from Linsoul.

Click here to view the earphones on their website, along with current pricing and additional information not contained in this review.

Packaging – Thieaudio Monarch MKII

The packaging of the Thieaudio Monarch MkII is a little underwhelming. It follows a similar design language of the cheaper and more expensive models in the companies line—a simple black cardboard box with a jewelry-style presentation and an outer sleeve.

When spending so much money, I enjoy being amazed. At half the price, the unboxing of the Kinera Skuld is an experience, and many other IEM manufacturers realize the value in providing an exciting unboxing. Perhaps Thieaudio should take notes and add a little more wow factor.

I don’t want to suggest it’s a terrible experience. It’s just the earphones are so unique they deserve a little more polish than their mid-priced offerings to distinguish them as a more luxury product.


The cable of the Thieaudio Monarch MKII has a modular design allowing listeners to switch easily between different connections.

Unfortunately, I was unimpressed with the accessories included in the box. There isn’t the usual amount on offer here, and I suspect the lack of eartips is down to finding ones with a suitable diameter to match the nozzle of the IEM. Eartips can change the sound significantly. While you can get aftermarket tips like Azla of Final installed, I wouldn’t advise doing so as you sacrifice sound quality.

In the package, you have two options. A comply style foam which I found caused the sparkle of the highs to decrease along with the sub-bass. However, the stock silicone tips worked very well, providing a secure fit and the best sonic performance.

Other than tips, the only extra you get in the box is a generic carry case with the Thieaudio Logo slapped on top. Brands like Campfire Audio have a bunch of bespoke accessories, including a carry case customized to each earphone. So I think Thieaduio has cheaped out (that’s ok if brands do this to keep the cost down on the IEM’s).

The carry case is a good size, and it was easy to get the Monarch inside with room to spare for a small DAP/DAC/Amp.

Build Quality & Design – Thieaudio Monarch MKII

Thieaudio Monarch MKII

Things take a step up when we get to the earphones themselves. Dare I say one of the most beautiful earphones released all year?

The relatively large resin body of the Thieaudio Monarch Mk2 is gorgeous. Its seamless and tolerances are flawless. They have opted to go with a metal nozzle instead of continuing the resin shell.

It makes them much more durable as resin and acrylic chips easily through use and abuse. 2-pin connectors have been the standard for Thieaudio IEM’s over the past few years. Again, they have chosen to use a flush-mounted system without protecting a recessed port or QDC cable.

As I said, the finish of the Monarch MK2 is worthy of its high price but where it shines (literally) is in its faceplate. It is simply gorgeous.

The faceplate is unique to every set of Monarch MkII. It has a burnt copper look with canyons and crevices that catch the light and reflect it to make it an eyecatching piece in both the hand and the ear. There is depth to it, and the more I look at it, the more I fall in love with it. It’s so simple but so classy, undoubtedly worthy of being a flagship on many other brands.

Thieaudio Monarch MKII Cable

The cable on the Monarch MK2 is near perfect.

The cable is also incredible, something that I am known to be crazy about here at Audiophile On. A bad cable can make a good earphone hard to use. When reviewing such products, Im constantly wary of warning others about the added expense of upgrading a cable. You won’t need to do that here. It damm near perfect.

Cord cables are not my favorite designs. However, this one is essentially the same one used on the NiceHCK Topguy. Where Thieaudio improved, it was in the connector system. Modular headphone cables are all the rage right now so why not jump on the bandwagon and do it better than Dunu themselves. Well, I wouldn’t say better, but the interchangeable system here is easier to use.

The benefit of such a cable is that if you have multiple source devices (Amps/DACs/DAPs), you can easily switch between them. That reduces wear on the two-pin connectors of the earphones. It’s a versatile and simple solution, and the plug-and-play route employed here is easy and intuitive.

Sound Quality – Thieaudio Monarch MKII

Thieaudio Monarch MKII during the testing process with the Dethonray Honey H1 Amplifier

No other earphone I have listened to in the past 12 months has given me as much joy as the Thieaduio Monarch MKII. It is one of those IEM’s that will make you question where we can go from here. The sound is jaw-dropping, leaving you wanting more and more. It makes you want to run through your entire music library and reevaluate. It makes you not feel bad about paying full price for them, especially in a hobby where buyers’ remorse is genuine. For me, it’s top tier; it’s rivaled by a few but not surpassed.

What makes them sound so good? Well, it’s a combination of factors, but most importantly, it comes down to tuning. Thieaudio, in my mind, has the absolute best team of engineers tuning their earphones right now. The produce hit after hit and rarely releases a product that doesn’t work well for the right buyer.

The tuning on these is everything I could ever want. A combination of Sub-bass rumble, mid-bass clarity, and a perfectly balanced and open midrange topped off by smooth and detailed treble. This earphone is remarkable, really special.

Clarity is Vital

I was testing the Thieaudio Monarch MKII with the Ibasso DX300 DAP during the review process.

It’s hard to balance transparency with impact. A sound that wows can wow for many reasons. The MK2 can wow because of the ability to put forward a natural tonality but remains unmuddied and let the listener enjoy every detail. Separation and imaging on the MkII are genuinely jaw-dropping.

At no point did I feel I wasn’t getting every detail, but I never felt overwhelmed. I found instrumentation blended yet distinct and easy to isolate when required. My focus gets drawn to one particular area of a musical passage. Then it’s forgotten about, and you get thrown back into the medley.

A hint of warmth – The Mk2 is not what I call a warm headphone by any means. However, there is just enough that it even further engages you and brings intimacy and engagement to certain tracks. Male vocals display this time and time again, displaying weight and grain.

The decay is exceptional – Treble can create a soundstage, so can spacing. For me, nothing makes music sound natural as a good note decay does. The Monarch MKII is the best I have heard in this area, even beating out the original Campfire Audio Solaris or IER-Z1R. Triangles are a good example, but you will find this is mid-bass instrumentation as well. A triangle strike doesn’t just instantly fizzle out. It hangs for a second before slowly dissipating as you would expect. Beautiful.


The sub-bass response is strong here but not as strong as the original Monarch we used for comparison in this review. It can hit very hard when required but doesn’t have the overwhelming nature of the original. It is more refined and still capable of basshead music. I like that they didn’t stray too far away in this area yet tightened things up.

Mid Bass

The midbass is far more controlled and detailed, and there is also not a significant jump to the midrange frequencies. It’s a smoother transition, and it’s about releasing the detail that I love to see in the mid-bass. I didn’t detect any bass bleed in the midrange; this is a very composed IEM.


In this area, we need to talk about detail, lots and lots of detail. It’s right there in your face at all times. It’s smooth with the warmth mentioned above, making it natural without the harsh metallic sound you may find on less refined BA earphones.


The treble is smooth but pushed forward along with the mids. That may be hard to understand, but I see it as the treble is very easy to comprehend without ever going to sibilant ground. It’s very non-fatiguing, yet it works so well you still get lots of clarity and detail.


The soundstage is just medium-large. There are earphones like the Solaris and IER-Z1R with larger apparent soundstages (probably as they both push the treble a little more). However, as I mentioned above, it is still very much on the large side and further enhanced with the decay and separation.

Thieaudio Monarch MK2 Conclusion

Thiaudio Monarch MKII

Yes, I know people hate when a review is overly optimistic. There is nothing I don’t like about the way the Thieaudio Monarch MKII sound. What’s the point in catering to the masses? Should I use artificial objectivity the same way reviewers focussed on clicks do? This site is my blog, and if I think something is the best, then, well, I’m entitled to say so.

Now I want to be clear; I don’t think this is the single best-sounding earphone. I never believed in that. A basshead will be far more suited to the Xenns up. A producer may find the Ety ER4SR of greater use. For me, there is a tier of headphones and IEM’s that all sit alongside each other. I can see an argument made for each. The Sony IER, the Unique Melody Mest MKII, and a few others sit up there, and now so do the Monarch in my standings.

The only difference is, in my mind, the Thieaudio Monarch Mk2 match them on sound, but they cost a whole lot less. These are lovely sounding earphones, and despite the price hike over the original, they still seem like great value to me.

The earphone of the Year 2021 – Highly recommended as an endgame IEM.

Audiophile On
Audiophile On is a website dedicated to high-end audio products. With over 15 years as a reviewer, all articles are hand-written by one person to allow the comparison of products. Headphones, earphones, speakers, amplifiers, or DAC's we cover here.

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