Thieaudio Monarch MK3 default shell front over white background
Thieaudio Monarch MK3 default shell front 3 quarter and rear over white background
Thieaudio Monarch MK3 default shell front closeup on accessory case from Bloom Audio gallery
Thieaudio Monarch MK3 Sunset Horizon finish front over white background
Thieaudio Monarch MK3 Sunset Horizon finish front with stock cable over white background
Thieaudio Monarch MK3 Butterfly finish front over white background
Thieaudio Monarch MK3 Butterfly finish front with stock cable over white background
Thieaudio Monarch MK3 Disco finish front over white background
Thieaudio Monarch MK3 Disco finish front with stock cable over white background
Thieaudio Monarch MK3 Aurora Mix finish over white background
Thieaudio Monarch MK3 Aurora Mix finish with stock cable over white background
Thieaudio Monarch MK3 Aurora Crystal finish front over white background
Thieaudio Monarch MK3 Aurora Crystal finish front with stock cable over white background
ThieAudio Monarch MK3 Aurora Pink B2
ThieAudio Monarch MK3 Aurora Blue B3
ThieAudio Monarch MK3 Black Widow C2
ThieAudio Monarch MK3 Green Glamour C3
ThieAudio Monarch MK3 Blue Buoyant C4
ThieAudio Monarch MK3 Red Romance C5
ThieAudio Monarch MK3 Deep Dungeons D1
ThieAudio Monarch MK3 Sea Vines D2
ThieAudio Monarch MK3 Red Vivid D3
ThieAudio Monarch MK3 Green Urchin D4
Thieaudio Monarch MK3 all available shell colors and finishes chart

Thieaudio Monarch MKIII | Flagship Tribrid Universal IEMs

Regular price$999.00


Thieaudio logo

A Brilliantly Re-engineered Threequel: ThieAudio Enhances Their Tribrid Legend with the Monarch MKIII

  • 2 Dynamic drivers, 6 Balanced Armatures, and 2 Electrostatic drivers
  • Balanced Tonal Signature: The MKIII maintains a studio-monitor-esque tonal excellence while offering focused sub-bass impact
  • Enhanced Ultra-treble Output: now features Sonion's EST drivers and increased frequencies for improved staging and resolution
  • Improved Bass Quality: enjoy better quality bass without sacrificing tonal integrity with ThieAudio's IMPACT2 subwoofer innovation
  • Upgraded thicker 22AWG stock cable with modular plug design including 2.5mm, 3.5mm, and 4.4mm smart-switch plugs
  • (x6) shell colors with (x15) faceplate styles now available for a customizable finish

Bloom's Take

With the Monarch MK2, ThieAudio captured the highly resolving nature and micro-detail presentation of a flagship experience and delivered them with impressive value for the money. It was easily a best-seller IEM, earned a seat at the table of Bloom Audio's "Best Bang for your Buck" IEMs, and was rated as one of the best IEMs in the world by a number of reviewers and critics.

These are extremely big shoes to fill... but ThieAudio may have done just that with the Monarch MK3.

The MK3 successfully maintains a core tuning balance and delivers an elevated level of technical performance with excellent bass extension, natural and lifelike mids, and improved treble that provides sparkle and shimmer without sibilance and stabbing. Additionally, the imaging and soundstage are a clear standout.

The packaging and accessory kit for the MK3 remains essentially the same and is largely shared across ThieAudio’s lineup. However, the stock cable has changed and is more akin to the Oracle MKII cable. And while the new default faceplate is gorgeous, one of the big draws of the MK3 is the range of customizations available with the shells and faceplates offering about 80 possible combinations making this a special IEM.

Whether or not you love the changes from the MK2, the price, performance, and design make a really compelling case for Monarch MK3 as a near-flagship quality $1000 IEM that approaches "bass-head" territory.

Read our full review here.

ThieAudio Monarch MK2 and MK3 side-by-side with stock cables on wood tray from Bloom Audio gallery


IMPACT2 (“Impact Squared”) is ThieAudio's latest technological innovation to change the personalized audio industry. IMPACT2 is a new subwoofer solution consisting of (x2) 10mm composite diaphragm drivers arranged in an isobaric design. The addition of another 10mm subwoofer significantly enhances the power and texture of the bass, while the in-house isobaric chamber design keeps the frequency and pressure constant. This means you can enjoy better quality bass without sacrificing tonal integrity.

Enhanced Ultra-Treble Output

The Monarch MKIII has been updated with Sonion’s latest EST drivers and re-tuned to better exhibit their full potentials. Thanks to the new tuning strategy, the ultra-treble frequencies at +15kHz to 20kHz have been increased for a more comprehensive upper frequency extension. Compared to its predecessor, the Monarch MKIII will have a greater sense of staging, atmosphere, and an overall enhancement in perceived resolution thanks to this extension.

ThieAudio Monarch MK3 frequency response graph with Monarch MK2 comparison

Balanced Tonal Signature

At the core of the MKIII is a commitment to tonal excellence. It retains a studio-monitor like tonal signature with a focused sub-bass impact for a clean, natural, detailed sound. Engineered with a true 4-way crossover with 9 separate passive components, the Monarch MKIII stays true to its tonal legacy. Thanks to IMPACT2 , the subbass is punchier, but the mids from 200Hz to 800Hz retain their ruler-flat neutrality. This tonality of the mids mimics the true sound of studio monitors used in recording studios to deliver accurate audio reproduction.

Furthermore, the MKIII mids have been revamped to better separate respective driver ranges for maximum output while minimizing the THD. This means the mids will sound higher in resolution while retaining the same monitor-esque tonality. The treble has also been slightly re-tuned to offer more coherency throughout the region, as well as little more clarity and definition.

ThieAudio Monarch MK3 with attached stock cable on sea green folding pouch with plant from Bloom Audio gallery


  • Drivers: Sonion EST, Knowles DWFK 31785 (x2), Sonio 28UAP (x1), IMPACT2 (x2 10mm Composite DD)
  • Crossover: 4-Way Passive with 4 Sound Bores
  • Sensitivity: 99dB @ 1kHz (+/- 1dB)
  • Driver Impedance: 20Ω
  • Frequency Response: 20Hz-40kHz
  • Cable: 4' 22AWG 6N OCC Silver-plated and Graphene Silver-plated
  • Termination: 2-pin 0.78mm with (x3) modular Smart-switch (2.5mm, 3.5mm, 4.4mm)

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Customer Reviews

Based on 3 reviews
Neil S.
Goldilocks: "This bed's just right! Wait, it seems to shake a bit."

I dither between giving these iems 3.5 and 4.5 stars. In short, the tuning is perfect for me: creamy and defined. The fit is great. But...the quality control seems shaky (literally). Within days of delivery there was a problem with the right iem separating too easily from the 2pin connector with the provided cable. It was unclear whether this was caused by the iem or the cable. I bought another, inexpensive cable from Amazon to check and indeed it seemed to be the cable. This was great news, as I love the sound of these buds. (Incidentally, I was on vacation for a month when I received the MKlll's and Bloom Audio was completely cool with the delay in a return if a return was necessary). THEN, I noticed the rattle. Again in the R iem. "Oh dear," says I. (See reddit comments about the rattle for Thieaudio's new HYPE2 iems). I have that faint rattle, but the sound seems unaffected, so I decided to keep the iems. Perhaps this is foolish, as I do worry a bit about the overall longevity of the MKlll. Why did I keep them? The sound. I tested them against 4 other iems, 2 more expensive and 2 less. They were the: UM Mest MKll($1500), 64 Audio U12t ($2000), FiiO FD7 ($600), and the Ikko OH10 ($179). They were "sandwich tested", that is listening to the same track 3 times using the test iems two times, sandwiching with a Monarch MKlll listen in the middle. The source was a FiiO M15S DAP, the source track was the first movement of Mozart's 21st concerto, Weiner Philharmoniker, Friedrich Gulda playing, Abbado conducting, Deutsche Grammophon, in Dolby Atmos. In short: the tuning, detail, and just plain listening pleasure of the Monarch MKlll's was superior to the OH10s (not surprising, but if you want a good sounding knockabout set of iems with good separation and lots of sub-bass, the OH10s are a very good buy). The MKlll's outshone the FiiO FD7s too. The FD7s are a good set of buds for the price, but somewhat harsh in comparison to the MKllls. AND, most importantly, the MKllls held their own against their pricier opponents. The U12Ts are superior in texture and definition, but not by that much. They're a great set of buds, unique. And I'd say it's a wash against the UM Mest MKll. When listening to the Monarch MKllls, I found that trying to maintain my critical listening stance was impossible after a couple of minutes - I just got lost in the music - for me, that's all I want. PS: I tried them against a $2k pair of Campfire iems which shall remain nameless - but those sounded a bit wild (sharp peaks, etc.) compared to the controlled, remarkably listenable tuning of the Monarch MKlll. I recommend them heartily, I also recommend buying them from Bloom if you're interested - but I'd ask them about the rattle issue and quality control of the Thieaudio products in general. They'll answer you honestly.

Almost perfect

I was looking to upgrade from my Moondrop Arias when the Monarch MKIII was released. I wanted the best listening experience and the Monarchs didn't disappoint. Anything I play just sounded so satisfying, I don't think I'm gonna need another pair of IEMs again.

I wanted to give 5 stars, but I have an issue with the jack, it seems that the 3.5mm connector is a bit crooked. Although it doesn't really affect the sound, it is not something I expected at this price point.

Nevertheless, still a great purchase!

Hi Rafael. Thanks so much for leaving this review. Sorry to hear that the 3.5mm connector is a bit crooked. That's definitely something that Thieaudio can replace for you!

Benji fish
End Game

I have $4000 Headphones and have tried all the other ones going up to $7,000 including Susvara and Phi 1266TC, Stax 0009S. These IEMs are better then all of those. I will say they are quite large so if you have small ears going with the Oracle MKII.

The soundstage is massive. Treble is elevated. Bass is monstrous which i really adore. One of the best sounding audio devices i have ever tried and will be happy with for a very very long time.

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