2DD+6BA+2EST Flagship IEM
Regular price $999.00 USD
Sale price $999.00 USD Regular price

IMPACT2: THIEAUDIO's latest innovation in personalized audio with a powerful subwoofer solution using isobaric design and composite diaphragm drivers.

Enhanced Ultra-Treble Output: The Monarch MKIII now features Sonion's electrostatic drivers and increased frequencies for a more comprehensive upper frequency extension, resulting in improved staging and resolution.

Balanced Tonal Signature: The Monarch MKIII maintains a studio-monitor-like tonal excellence with clean, natural, and detailed sound, while offering a focused sub-bass impact.

Improved Bass Quality: The addition of another 10mm subwoofer in IMPACT2 enhances the power and texture of the bass without compromising tonal integrity, providing better bass quality for an immersive audio experience.

THIEAUDIO Monarch MKIII - Default option

THIEAUDIO Monarch MKIII - Default option

Monarch, Pushing beyond the Pinnacle

At their times, the original Monarch and the Monarch MKII set new standards for best-in-class performance in the global IEM industry. Not only did it redefine the price-to-performance bracket, but it forever changed how IEM manufacturers engineer and tune IEM’s. Keeping with the times, the Monarch has undergone another revision to revamp its technical and tonal performance.

THIEAUDIO Monarch MKIII - Custom with Black Bat shell and Disco Faceplate option

Monarch MKIII - Custom with Black Bat shell and Disco Faceplate option

Enhanced Ultra-Treble Output

The Monarch MKIII has been updated with Sonion’s latest electrostatic (EST) drivers and re-tuned to better exhibit these drivers’ full potentials. Thanks to our 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 the treble extension. 

Balanced Tonal Signature

At the core of the Monarch MKIII is THIEAUDIO’s commitment to tonal excellence. The Monarch MKIII retains a studio-monitor like tonal signature with a focused sub-bass impact for a clean, natural, and 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, compared to its predecessors, the Monarch MKIII mids have been revamped with a new tuning strategy, which better separates respective driver ranges to maximize output while minimizing the total harmonic distortion. This means the mids on the MKIII 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. This slight tonal modification better mixes with the renewed ultra-treble response, providing a more crisp sound signature. 

THIEAUDIO Monarch MKIII - Custom with Black Bat shell and Sunset Horizon Faceplate option

Monarch MKIII - Custom with Black Bat shell and Sunset Horizon Faceplate option


From a nameless group of DIY enthusiasts to one of the best acclaimed IEM brands in the world, THIEAUDIO has made an incredible journey in the pursuit of high-fidelity audio. THIEAUDIO has become a staple brand in audiophile communities around the world, beloved for its best-in-class tunings, superb technical performances, and budget-friendly pricing. From the start, the THIEAUDIO team has put audio quality at the forefront of each project, aiming to be the Robin Hood of the audio world by bringing the best sounding audio solutions at the most affordable prices. Since its launch in 2019, THIEAUDIO’s legacy of in-ear monitors has forever changed the world of IEM’s, influencing how global manufacturers of earphones engineer their products. THIEAUDIO’s international team of few, but dedicated engineers from China and South Korea are committed to continuing this legacy by creating innovative, yet affordable, audio solutions that will leave you in awe.

THIEAUDIO Monarch MKIII - Custom with Black Bat shell and Butterfly Faceplate option

Monarch MKIII - Custom with Black Bat shell and Butterfly Faceplate option

Inside the Box

  • 1 x THIEAUDIO Monarch MKIII
  • User Manual

1 Year Warranty

The THIEAUDIO Monarch MKIII Comes with a 1 year warranty on the In-Ear Monitors and 3 month warranty on the cable.

Technical Details


In-Ear Monitors


Sonion EST, Knowles DWFK 31785 (x2), Sonio 28UAP (x1), IMPACT2 (2 x 10mm Composite DD)


4-Way Passive Crossover with 4 Sound Bores.


99dB @ 1kHz (+/- 1dB)


18 ohms

Frequency Response


Cable Details

1.2 meter 22AWG 6N OCC Silver-Plated and Graphene Silver-Plated Cable 

Cable Connectors

2-pin 0.78mm

Cable Termination

Modular Termination with 2.5mm,3.5mm,4.4mm Interchangeable plugs

$999.00 USD

Processing Time

This product is in Pre-order period. Pre-orders are provided for items that have not reached us and will take some time to be shipped out.

Processing time: Depends on design

  • We may have in-stocks for UIEM (default batches). Check this with us
  • 6-8 working weeks for UIEM with custom design
  • No cancellation of UIEM (custom design) orders once ordered

    Images are for reference only. Actual product and packaging may differ from the images. Final product is based on what is actually received.


  • No cancellation of orders once ordered.
  • All orders to be shipped out sequentially.

Authentic Products

Linsoul Audio is the authorized distributor. All products are authentic and genuine.

Worldwide Free Shipping

We are located in China but send our products worldwide for free. T&Cs apply.

1 Year Warranty

We provide 1 year warranty for the all products except the cables and accessories*.

Online Support

Need help?, we are here to assist you
Monday - Friday: 09:00 – 18:00 (UTC+8)

Customer Reviews

Based on 3 reviews
Love these!

I had originally shortlisted the Mk IIs and right as I was planning to buy those, the Mk IIIs were announced and made available. The fact that these were being sold at the same price intrigued me and so I took a risk and bought it. The MK IIs were tried and true and got rave reviews but the fact that their sound signature was extremely neutral gave me pause. I wasn't sure if I would take to if immediately and accepted that it would need to grow on me. So when I saw that the tuning for the MK IIIs would be to boost certain aspects of the soundscape I really thought I might.prefer it over the MK IIs.

With all that, I couldn't be happier with the results. This was my first IEM and well worth the price for the sound quality and clarity. It has warmth, vibrance, brightness, and just...character. All things I wasn't sure the MK IIs were going to have despite its audiophilic excellence. Keep in mind, I AM NOT recommending a blind buy, of this or any product. Especially not when the price is this high. Please do your own research and be sure that this is what you want, especially over the MK II, as what I listed as positives may be negatives for someone else. This particular purchase just happened to work out for me. The fact that I had no proper experience or expectations for how an IEM should sound definitely helped as well, I think.

TLDR: I personally loved this product and would wholeheartedly recommend it to someone who doesn't want a "pure" audiophilic sound. If you do, go for the Mk II instead.

Initial impression - Most excellent

I was lucky to receive it earlier than expected and I have just spent the first day listening to it.
So far this meets and even exceeds my expectations and for me it is definitely a worthy successor to the Monarch MK2.
The two new dynamic drivers really bring back the midbass. The midbass was the one thing I found lacking in the MK2.
Even though the low-end has been turned up and the bass is more visceral it still keeps the tonality and technicality I have come to expect from the Monarch series.
The MK3 has better tonality and tuning for my music library and I think Thieaudio is going to have a great success with their new Impact2 driver setup. I'm really looking forward to it in the Hype 2 as well.
This IEM is going into my all-time top favourites together with 64 Audio U12t and U4s. I hope the MK2 is still going to stick around for those that want a leaner tonality without having to EQ, though I don't think you could EQ to give MK3's feeling of slam into a MK2.

It's slightly on the larger size, but I found it very comfortable for long listening sessions and the weight is a non-issue. I find it as comfortable to wear as my 64 Audio's. I also prefer the cable over the MK2 cable, as the MK2 was a bit cumbersome.
The default faceplate looks awesome.

First Impression: Can't Stop Won't Stop

I have not watched or read any reviews prior to this. As a former owner of the MKII, I was definitely swayed by the announcement of the MKIII.
Blessed by DHL Express for its speedy delivery, blessed by THIEAUDIO for its superb team of audio engineers.
The MKIII is slightly smaller than the MKII but it is not as small as the 1st generation Prestige. The slightly smaller shell size of the MKIII does make a difference in comfort. However, after long hours of listening, your ears may still go numb if they are small. Mine felt numb around the 2nd hour.
Thankful that THIEAUDIO also decided to change MKIII's cable to Prestige's. The MKII has a chunky and heavy cable which affected my overall listening experience.
I no longer have the MKII to compare its sound with the MKIII. However, balanced detailed beast remains a balanced detailed beast. Everything sounds so clean, especially its subbass. As a former drummer, I really love how the kick drum punches for every song with drums. So tight and punchy. It just sounds so right. Treble sounds detailed with sparkle without piercing.
The only concern I have so far is that a few songs sound so detailed that it can be fatiguing e.g. Michael Jackson's Beat It and Billie Jean.
Two hours into listening and I am really enjoying it. I only stopped because my audio player ran out of battery and my ears started feeling numb.
The faceplate looks freaking cool, much nicer when you see it in person.

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