ThieAudio Monarch MKII Review

Out of all of the various ChiFi brands that are out there, ThieAudio is one brand that I haven’t heard much from. A while ago a reviewed the Legacy 4 and was really impressed by them, but since then I haven’t been able to hear much from TheiAudio’s vast library. That was until I got my hands on the Monarch MKII. I’ve heard a lot of good things about the original Monarch, and I’m excited to dive into this $999 IEM. Let’s see if their premium selection is all it’s cracked up to be.

ThieAudio Items

What You Get

  • Monarch MKII IEMs
  • Ultra-pure Silver-plated OCC Copper 26AWG Litz Wires
  • 2.5mm 3.5mm and 4.4mm terminations
  • Cleaning cloth
  • Carrying case
  • Extra sets of silicone and foam ear tips

ThieAudio single

Look and Feel

In terms of style and artistry, the Monarch Mark II really brings its A-game. The housing is big but instantly eye-catching with its glistening design that features multiple colors under a glossy resin shell. I’m personally a fan of the MKII’s shorter nozzle here, and the selection of ear tips that ThieAudio gives you a bit more leverage with the fit, but their comfortability really comes down to the size of the housing. My ears are big but at times the shell becomes a little distracting. I didn’t feel any fatigue at all, even after long hours of listening, and the feel of the earphones is still light. However, it didn’t fit as naturally with my concha as others do, so the security of the MKII is brought into question.

ThieAudio Cable


There’s a ton going on inside of the MKII’s housing, with a driver system that gives the signal flow a ton of potential. This tribrid powerhouse comes packed with a single 10mm dynamic driver, six balanced armatures from Knowles, and two electrostatic drivers from Sonion. The composite diaphragm on the dynamic driver has increased tension and strength for superior responsiveness. For the Knowles armatures, the mid-frequencies were its core concern and ThieAudio doubles the number of drivers while reducing interference for enhanced articulation. With electrostatic drivers, the chance for unwanted resonance is always a possibility, but the MKII arranges them in a way that helps minimize that tubing interference.

ThieAudio Front


When I’m listening to the MKII I get the feeling like the soundstage could be wider, but the stereo field only goes so far. It reaches far enough for the sound elements to show natural distinction and realistic positioning, but there seems to be a limit on how far the extreme left/right channels can go. It’s not quite shoulder length but still extends enough to make the imaging feel complete. Although the MKII might have its shortcoming when it comes to width, the depth is excellent and showcases its layers clearly.

Treble frequencies are placed firmly above the other ranges of frequency, adding significant height to the image. It places the rest of the frequency response in neat stacks that move around the space easily, creating an engaging sonic environment. It tidies up orchestral performances, as well as progressive rock odysseys, making the MKII succeed in bringing exceptional musicality to the sound signature. Although I think they could have gone bigger with the soundstage, the separation and layering present a level of depth that’s instantly gratifying.

Low End

There’s a bass presence here that is excellently performed in its control and texture. You won’t get booming sub-bass, but instead, one that’s subtle in its edge. It grants the bass an impactful display but tightens its resonance for a more natural response. It also makes the mid-bass a lot more punchy in tone while at the same time smoothing out its more accentuated details. Texturally this is a purified bass timbre that cares about its details more than it does its tone, providing a low-end that satisfies those who are looking for an accurate picture of the bass rather than one that possesses an abundance of thick frequency content.


The smoothness of the mid-bass works its way well into the midrange but does not bleed and destruct its timbre. These mids are actually very well detailed, and the quickness of its transient response highlights that aspect considerably. With the MKII you get a little bit of the best of both worlds, with the warmth of the low-mids and the richness of the fundamental and upper-mids that make this sound signature shine. Instruments like pianos and horns have the perfect amount of drive to them, while vocals sit above them in a more forward position, offering a commanding presence.


While you don’t get as much richness in the treble, the frequencies are still crystal clear and feature refined details without falling into the fatiguing territory. Its sparkle is light but perceivable, adding texture to elements like the chirping of birds from James Horner’s score to “The New World.” I felt like there was a sweet ring to the frequencies here that delivered the same control as the bass but in a more freeing manner. There’s brightness, but it should never distract from the detail, offering a tonality that heightens the timbre without becoming hard to digest. These highs go down very easily and should satisfy treble lovers, as well as those who just want a detailed frequency response.


I found there to be a ton of great qualities about the Monarch MKII that sets it apart from the common horde of IEMs in this price range. What it lacks in width it more than makes up for in separation and depth, not to mention the balanced and textured details that can be heard across its frequency response. The fit wasn’t for me, but the design of the shell itself makes for a striking appearance that’s sure to stick out. At the end of the day, the MKII offers strong competition to the current crop of thousand-dollar IEMs.

ProsĀ  Cons
  • Deep imaging
  • Great separation
  • Tight sub-bass
  • Rich midrange
  • Detailed highs
  • Striking design
  • Cable
  • Housing is a bit too big

The ThieAudio Monarch MKII 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.