ThieAudio Monarch MKIII Review

ThieAudio Monarch MKIII Review

One of the standout ChiFi product lines has been the Monarch series from ThieAudio. They’ve revised the Monarch twice now, with the MKII, and now the MKIII. Like all the other Monarch IEMs, they cost $999, but does the MKIII offer enough enhancements to warrant an upgrade?

ThieAudio Monarch MKIII items

What You Get

  • Monarch MKIII In-Ear Monitors
  • 22AWG 6N OCC Silver-Plated and Graphene Silver-Plated Cable With Modular System
  • 3 Pairs of Silicone Ear-tips
  • 3 Pairs of Foam Ear-tips
  • Carrying Case

ThieAudio Monarch MKIII single

Look & Feel

ThieAudio shrunk the shell of the Monarch with the MKII, and they’ve fittingly kept that design for the MKIII. You’ll always get great artistry on the faceplate, supported by medical-grade resign that really makes things pop. The housing has the same ergonomic shape as many of their similarly priced models. It helps make the fit feel natural, like the shell is perfectly molded to your ears. The MKIII is very comfortable, providing a good seal and isolation.


Inside of the MKIII is tri-brid configuration that features dual dynamic, six balanced armatures, and two electrostatic drivers. This design is supported by a new innovative structure called IMPACT2 which acts as a subwoofer. That’s why the MKIII has two dynamic drivers, as one of them contains this IMPACT2 component. It also features a 4-way crossover that has 9 separate passive components.

ThieAudio Monarch MKIII pair


The Monarch series consistently delivers great soundstage and imaging. With the MKIII, everything is refined and operates smoothly. You get an extensive width that sucks you in to the music from the first time you hit play on your first track. What stuck out to me almost immediately was how exceptional the spatial imaging performed this time around. Past versions of the Monarch had great imaging too, but on the MKIII, everything seems to be placed more concisely.

It comes through with incredible realism, with instruments and effects jumping out in front of you and displaying intricate layers that highlight distance. It’s the type of soundstage that acts like the music is being performed for you instead of directly from drivers. In a way, the MKIII can be considered holographic, but nothing about it seems like the sound is performing inside of a bubble. The stereo accuracy of the MKIII is just so emphasized that it creates so much natural immersion.

Low End

Previous versions of the Monarch all feature a hefty bass response, so the MKIII feels right at home here. The MKIII has a gripping bass timbre that digs deeps, and sustains a large impact. It’s the kind of tone that will easily satisfy bass-heads, but offers enough cohesion and clarity to make sure the sound is still dynamic and gratifying. There’s body and shape throughout most of the frequency range, expanding from the sub-bass to the mid-bass. It gives the sound signature great texture, as well as impressive finesse.


There’s a striking nature to the highs on the MKIII, even when they perform more flatly compared to the rest of the frequency response. The frequencies comes through with a ton of transparency, but a standard surface of detail. You get some slight boosts in the low-mids with some of that expressive bass making its way through, but everything else remains pretty neutral. This tuning never works against the timbre of the mids, as they always come across as being fully unveiled and alive. This is accentuated by exceptional upper-midrange response, which gives instruments and vocals a sublime underlining tone of vibration. It makes every note come off with a specific identity, calling attention to its attack and decay.


For someone who craves colorful and detailed highs, the MKIII is a treat. Its timbre offers a crisp response, with elements of glistening frequencies. The brightness is never an issue, as it’s controlled in a way to only bring out qualities that compliment the region rather than display harshness. The treble has sparkle and it makes the sound elements tail off with a satisfying ring. It’s an addictively biting response that made me eager to keep testing the MKIII with different genres.


I had expectations for the Monarch MKIII based on previous iterations of this series, and they’ve all been shattered. When I hit play on the first track wearing the MKIII, I knew I was in for something special. The soundstage captured me immediately, followed by its invigorating bass and lush instrumental response. Everything about the sound is superbly textured, while also balancing its frequency response with dynamic range, leaving enough room for tighter control over the sound signature. With a comfortable fit, great design, and quality stock cable, you have one of the best thousand dollar IEMs out there right now.

The ThieAudio Monarch MKIII is available at Audio46.

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Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.