(Last Updated On: January 29, 2021)

Are the Monarch the true king of the IEMs, or are they only beautiful butterflies?

Thank you to Linsoul for providing the Thieaudio Monarch for review purposes. If you’d like to purchase the Monarch, they are available from Linsoul for USD $730.

How the long-established brands must hate the name Thieaudio. Over the last couple of years, the house brand for the Chinese audio company Linsoul has mercilessly released a flurry of mid-range IEMs. Each worthy of discussion, consideration, and a contender for the title of ‘best’ at their respective price range. Each features an impressive combination of miniature drivers and technology.

Recently Thieaudio released a pair of TOTL tribrid IEMs that they refer to as their Signature Series. These two IEMs are targeted squarely at the diminishing returns of the high-end IEM market. Thieaudio intends to prove that kilo-buck (and beyond) performance is achievable for significantly less money.

A tribrid, much like a hybrid, uses multiple driver types in a single IEM. Hybrid = two driver types. Tribrid = three. The Monarch combines (a mind-blowing) one dynamic driver, six balanced armature drivers, plus two electrostatic drivers in each IEM shell!

The Monarch (USD $730) and Clairvoyance (USD $700) tribrids have received fairly universal praise in headphone circles. The internet buzz has been intense. I’ve had the opportunity to review several of the lesser Thieaudio siblings (Voyager 3, Legacy 3, and Legacy 5) and am quite impressed with all of them.

The Monarch are beautiful.

Thieaudio Monarch

"It’s very difficult to find fault with their technical performance. The level of clarity and presence in the Monarch is jaw-dropping. Bass gravity and complexity is astounding. The Monarch sound unique in the IEM universe and are SO very compelling to listen to. Fine. They are expensive. Want to just chill and do other things when listening? Nope. The Monarch won’t let you."

Pros:

  • »Outstanding sub-bass depth and control
  • »Natural yet compelling sound
  • »Astounding detail retrieval, clarity, and presence
  • »Gorgeous build quality and faceplates
  • »Excellent included cable and accessories

Cons:

  • »Large size may not fit smaller ears
  • »Midrange laid back and a bit dry
  • »Not for background listening

So, it should come as no surprise that I am very excited to try one of the tribrid twins.

However, with excess excitement comes raised expectations. The Monarch are far from inexpensive. Can they still impress? Can they live up to their hype and potential? Can the Monarch rule as ‘king of the IEMs,’ or are they more butterfly than lion?

Let’s find out.

The build complexity and high consumer demand mean that there is often a delay (as of writing 30 days) for Linsoul to manufacture the Monarch before shipping.

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Simply gorgeous.
Simply gorgeous.

Company Overview

Thieaudio is a creative endeavor of Chi-Fi mega-company Linsoul Audio. Founded in 2019, the “…goal of Thieaudio was to serve as a creative platform for gathering the best teams of engineers … For each project, we hand-select the most innovative and renown engineers in his or her field to oversee the design, engineering, and manufacturing of the products.”

The Thieaudio Voyager and Legacy IEM series are both headed by master audio engineer Chongjun and “were created to bring about unparalleled sound performance that would rival the leading international brands.” The Voyager series is intended for musicians, while the Legacy series’s intended audiences are audiophiles and music enthusiasts.

The faceplates may resemble butterfly wings, but these IEMs roar like lions.
The faceplates may resemble butterfly wings, but these IEMs roar like lions.

Technical Specifications

  • Price: USD$730
  • Form: IEM
  • Drivers: Electrostatic tribrid: 10mm dynamic driver + 6 balanced armature drivers + 2 electrostatic drivers
  • Impedance (Ohm): 26 Ohm
  • Sensitivity (dB): 112 dB @ 1 kHz
  • Frequency Response (Hz): ?Hz – 80 kHz
  • Removable Cable: Y
  • Source Jack: 2.5mm TRRS
  • Cup/Shell Jack: 0.78mm, 2-pin
  • Mic: N
  • Weight (g): 14 g (with Spinfit tips and no cables)
Thieaudio's new standard simple green box packaging.
Thieaudio’s new standard simple green box packaging.

Packaging

Thieaudio uses the same packaging and accessories for most of their headphones these days, differing only by the label on the side and your selected options. The good news is that it’s one of the best bundles around. If this is going to be the standard going forward, it sets a high level for their competitors to match.

The faux leather storage case is roomy enough for all the accessories.
The faux leather storage case is roomy enough for all the accessories.

The Monarch are packaged in a large, dark green, square cardboard box. Sliding it open, you’ll find a vellum insert with ‘Thieaudio’ embossed in the center in gold. Underneath, nestled in felt, you will find the IEMs above a classy looking brown (faux) leather folding case. The case looks a bit like a large wallet or small clutch handbag.

In the box

  • Thieaudio Monarch with SpinFit CP100 ear tips (M)
  • 3 sizes (Small – purple, Medium – mustard, Large – green) memory foam ear tips
  • 4-core 5N-Litz silver-plated OCC 100 copper cable (2.5mm balanced)
  • Brown leatherette carrying case
  • 2.5mm to 3.5mm TRS adapter
  • 2.5mm to 4.4mm pentaconn balanced adapter
This is a terrific bunch of included accessories. The adapters are especially welcome!
This is a terrific bunch of included accessories. The adapters are especially welcome!

Cable

The included cable is the same terrific Litz 5N OCC, 100 wire, 4-core silver-plated copper cable offered as an upgrade for other Thieaudio IEMs. While it’s not the softest and most flexible cable I’ve ever encountered (the Tripowin C8 holds that honor), it’s pretty close.

The cable features a twist structure rather than a more common braid. Additionally, the cable is terminated with a balanced 2.5mm plug and includes matching high-quality adapters for use with 3.5 single-ended amplifiers and 4.4 pentaconn balanced devices. Unfortunately, because the adapters are straight (rather than 90 degrees), the plug plus adapter length becomes unwieldy with a portable device.

If only the adapters were right-angled rather than straight.
If only the adapters were right-angled rather than straight.

The installed ear tips are medium-sized Spinfit CP100. Spinfit claims that the CP100 has an “inner diameter of 4 mm… Upgraded sound, lengthend [sic] umbrella and softer silicon used… Ergonomically designed with the ability to flex in all direction and conform to the ear canal… Deeper & clearer sound. Improves sound quality overall in bass, treble, and sound stage.”

Additionally, included are three pairs of soft memory foam ear tips. I stuck with the silicone ear tips for most of my listening, and this is what my review notes are based upon. Factoring in the cable, adapters, ear tips, and case, this is one of the finest included batches of accessories I’ve seen, regardless of price.

Design

Thieaudio is garnering a reputation for producing gorgeous and perfectly finished IEMs, and unsurprisingly, their flagship Monarch are no exception.

The shell and glitter combo certainly is eye catching.
The shell and glitter combo certainly is eye catching.

The Monarch shells are quite large, likely due to the nine drivers contained inside each one. All that tech has to fit in there somewhere! The Monarch are significantly more sizable than the Legacy 5.

The shells are made of an almost-opaque dark acrylic, with no visible seams. The faceplates are a striking vertically-divided combination of multi-colored glitter and blue/green iridescent abalone shell. “THIEAUDIO” is classily written across the middle in thin silver capital letters. For an additional $60, Linsoul offers over 50 choices of custom color designs available to choose from, although you’ll be hard-pressed to select a better-looking combination than the stock design.

The Monarch are also available as custom IEMs (CIEMs).
I'm relatively certain I couldn't make a more attractive face plate.
I’m relatively certain I couldn’t make a more attractive face plate.

The nozzles are of average length and share the same silver metal design used on the Legacy 5. However, the Monarch nozzles feature a raised lip around the edge, making ear tip exchanges far more difficult. But this does mean they won’t come off in your ears when removing the IEMs. A vast improvement in my book! The fine grill mesh inside the tips appears to be the same as used in the Legacy 5.

Earlier released versions of the Monarch do not have a lip around the edge of the nozzle.

I approve of the small, subtle blue (left) and red (right) colored vents on the top surface. The connectors are the flush, 2-pin 0.78mm variety.

Differing the vent colors is a subtle yet effective way of determining the left (blue) and right (red) sides.
Differing the vent colors is a subtle yet effective way of determining the left (blue) and right (red) sides.

Comfort

Although the Monarch are noticeably larger feeling in the ear than the Legacy 5, their smoothly-contoured ergonomic shape remains comfortable, even for extended listening sessions. If your ears are small and you struggle to find IEMs to fit, the Monarch may not be for you.

Impressively, despite the additional drivers, the Monarch only weigh 1 gram more per shell (7g vs 6g with Spinfit tips installed) than the Legacy 5.

Although vented, the Monarch isolation is about average for IEMs, and I find that they stay securely in my ears. These will serve well for high-fidelity listening while commuting or out and about.

The difference in size between the Legacy 5 (left) and the Monarch (right).
The difference in size between the Legacy 5 (left) and the Monarch (right).

Internals

The tribrid design is a relatively new phenomenon in the IEM world. The Monarch feature a combination of a custom 10mm dynamic driver (the same as found in the Legacy 5), paired with authentic American-made Knowles BA drivers and Danish-made Sonion electrostatic drivers.

One dynamic driver, six balanced armature drivers, plus two electrostatic drivers are contained in each shell.

The two electrostatic drivers are most likely a variation known as ‘electret’ drivers. A true electrostatic driver requires a high bias voltage (and associated amplifier), while an electret uses a static pre-charged membrane suspended between to metal stator plates.

The benefit of using different driver types (and a high driver count) is the opportunity to take advantage of each driver’s unique strengths. To do this properly requires an incredible combination of expertise and technology. Other companies have tried to include as many drivers as possible in an IEM and have ended up with a non-cohesive sounding mess. I’m looking at you KZ ASX.

The Monarch even look nice in pink.
The Monarch even look nice in pink.

More is not always better, especially when it comes to IEM drivers.

“Gathering the momentum from the success of the Thieaudio Phantom planar magnetic headphones, and the Voyager and Legacy series In-Ear Monitors (IEM’s), the two new monitors utilize the latest driver technology from the Danish manufacturer, Sonion – the Electrostatic (EST) tweeter. The EST driver features an ultralight membrane in a small tweeter chamber that is powered by an independent transformer to extend the in-ear monitor’s treble range up to 80kHz” – Linsoul

The Monarch utilize a 4-way passive crossover and four bore tubes in each shell to achieve their signature tuning.

Yet, all that technology is pointless if they do not sound good.

Monarch Sound

Wow.

Now I realize you probably are looking for slightly more detail than a single word to describe the Monarch sound. However, that one word pretty much covers how I feel about the Monarch.

In a nutshell, extraordinary sub-bass response, paired with a lean but uncolored midrange, defines the Monarch. Treble response is articulate and sweet. They excel with any type of music and impress with their technical abilities.

Likely due to the electrostatic drivers’ requirements and the associated required tuning and dampening, the Monarch benefit from (and deserve) proper amplification. Although with an impedance of 23 Ohms and 112dB (@ 1kHz) sensitivity, the stock Apple 3.5mm dongle can reasonably drive them.

I completed the bulk of my listening with the Monarch with a Hidizs AP80 Pro DAP serving as a Chord Mojo DAC/amp source. File format and music style varied, but I did most of my listening in the relatively quiet confines of my home.

The Monarch sound is immaculate and has excellent imaging, although the soundstage remains relatively standard for IEMs. That is, they are somewhat confined to an ‘in-the-head’ experience. Detail and resolution are astonishing, however, and instrument separation is terrific.

The sun really brings out the variety of colors in the faceplates.
The sun really brings out the variety of colors in the faceplates.

These might simply be uninteresting, albeit quite refined, reference studio monitors if not for their prodigious sub-bass response. The midrange is uncolored, without much added warmth, which can come across as somewhat sterile and lean. However, this does heighten the impression of clarity and detail. Musical coloration (and the Monarch’s unique personality) comes from sub-bass power and depth, delicately balanced by exceptional treble clarity and energy.

The Monarch are not IEMs for background listening. They demand and deserve your full attention. Some IEMs allow me to work, write, or read while listening. The Monarch are not that sort of IEMs. They command attention and reward with a magical listening experience.

“…the Monarch was designed to bring out the best that In-Ear Monitors can offer. The sound signature had to be analytical to bring about precision and a reference-style tuning. This necessitated a linear midrange section which would place all instruments balanced with one another and provide an overall clean and lean sound

The mid-treble transition peaks at the inner ear canal resonance point and is sustained through the entire upper-frequency range to maximize detail retrieval and overtone presence. Yet, careful attention was placed in making the trebles smooth and void of sharp peaks or dips to eliminate any uncomfortable upper harmonic irregularities.” – Linsoul

The frequency response measurement graph for the Thieaudio Monarch. The above frequency response measurements use an IEC-711 coupler based on the IEC 60318-4 standard. Note that there is a resonance peak at around 8kHz and these devices do not simulate a human ear below 100Hz or above 10kHz.
The frequency response measurement graph for the Thieaudio Monarch. The above frequency response measurements use an IEC-711 coupler based on the IEC 60318-4 standard. Note that there is a resonance peak at around 8kHz and these devices do not simulate a human ear below 100Hz or above 10kHz.

Bass

Let me give you the low-down on the Monarch sound. The down-low. The so… very… LOW. Oh, that marvelous sub-bass response. Full, deep, and weighty, yet entirely controlled.

The mid-bass response is a bit less exciting in comparison, but it is entirely acceptable. There are decent slam and impact, and layering and texture are very well maintained. Unlike many hybrid IEM designs, the bass is not solely the dynamic driver’s purview, but four of the balanced armatures are also tasked with adding to these frequencies.

While bass-heads, or those who primarily listen to music with a sub-bass focus, will likely find a lot to like with the Monarch, I don’t mean to convey the impression that they are overly ‘bass-heavy’. Rather, they are quite balanced sounding. The sub-bass thunder can be quite awesome with the right song, but the rest of the frequency spectrum remains extraordinarily coherent and present.

She's so pretty in pink.
She’s so pretty in pink.

Midrange

The Monarch midrange presence lags behind the high and low-frequency extremes. The mids are very flat from 150-900 Hz, followed by a rise from 1-2.5 kHz. This presentation has both benefits and drawbacks. Vocals and instruments have great separation. The Monarch midrange renders tons of detail and is uncolored and realistic sounding.

Yet, some might find this presentation dry and a bit sterile. Those who are bothered by balanced armature timbre and sound will likely not have their minds changed by the Monarch. I wouldn’t describe the Monarch midrange as lush, although any audible grain is very minimal. The Monarch err on the clinical side, and depending on your sensitivity and source material, they can border on being somewhat sharp sounding.

The Monarch midrange presents the music cleanly and without a veil. It’s all there for the listener, all the good and all the bad. Nothing is hidden, but the mids don’t jump out and demand your attention. The midrange is impressively detailed but a bit set back in the overall mix.

Treble

CLARITY AND PRESENCE!

I feel like I should be writing this section in all caps with multiple exclamation marks to try to convey my Monarch sound impressions, but I’ll try to contain myself.

The Monarch empower music with an extraordinary amount of energy. I attribute this characteristic to the inclusion of electrostatic drivers. If so, you may consider me a tribrid convert.

Somehow all the upper-frequency dynamism doesn’t devolve into sibilance or become too strident. The Monarch are articulate and crisp but are so quick that there is no unnatural shimmer or glaze to the sound.

The treble is subsequently present (and frankly, in-your-face) so you can’t maintain any distance from it. Perhaps it’s due to their natural timbre and lack of thinness that the Monarch treble response is captivating rather than fatiguing. Coherent and not too extended, with detail in abundance. I said it before, and I’ll say it again. Wow.

I can’t possibly just sit and listen to these IEMs without moving. I am entirely unable to work or do anything else but surrender to the music when the Monarch are in my ears. If the music says “dance,” then dance, I must. Their presence is that commanding. They move me, in every sense of the word.

Let me be clear. The Monarch set the standard by which I will judge absolute sound quality going forward.

Legacy 5 Comparison

Unfortunately, I do not have the Monarch’s twin, the Clairvoyance, on hand to compare the two.

The obvious comparison that I can perform with the Monarch is to the Thieaudio Legacy 5. To justify the (more than double) price tag, the Monarch must offer a significant sound improvement over their high performing little brother.

In short, they do.

The Legacy 5 (left) and Monarch (right).
The Legacy 5 (left) and Monarch (right).

Soundstage, imaging, and resolution are better with the Monarch. It’s evolutionary rather than revolutionary, but there is a noticeable improvement when performing A-B comparisons. The Monarch seem faster and much more coherent. Their level of detail retrieval is simply on another level. Treble response is far and away more captivating using the Monarch.

Despite sharing the same dynamic driver, the Monarch bass is much more layered and extended. It seems likely that the Monarch’s pairing of balanced armature drivers with the dynamic driver makes the difference. The bass digs deeper, yet has additional control and finesse.

The Legacy 5 are great IEMs at their price point, but they fall flat when compared to their big brother. The Legacy 5 share the same build quality, and I’ll give the Legacy 5 the nod on comfort, as their (comparatively) diminutive size is easier to fit in smaller ears.

Where to Buy

Conclusion

The Thieaudio Monarch have set a new standard (for me at least) in IEM fidelity and performance. They’ve introduced me to the use of electrostatic drivers in IEMs and the concept of the tribrid. Additionally, they’ve cemented Thieaudio’s reputation and legitimacy as one of the best current IEM manufacturers.

Thieaudio’s tribrid triple threat has rocked my little world.

Fine. They are expensive. And their forward and somewhat dry approach to musicality may not be for everyone. Those looking for the lushest midrange may feel somewhat short-changed. Want to just chill and do other things when listening? Nope. The Monarch won’t let you.

The Monarch sound is just as beautiful.
The Monarch sound is just as beautiful.

It’s very difficult to find fault with their technical performance. The level of clarity and presence in the Monarch is jaw-dropping. Bass gravity and complexity is astounding. The Monarch sound unique in the IEM universe and are SO very compelling to listen to.

I feel somewhat bad for the other IEMs in my stable. They are simply not going to get much ear-time from here on out. The Monarch’s roar rules me, and I kneel and bow my head in respect to the new king.