Get insider access
Preferred store
Your browser is not supported or outdated so some features of the site might not be available.
We've recently released our Test Bench 1.8 update for Headphones! Read the R&D Article to learn more.

THIEAUDIO Monarch MKIII Headphones Review

Tested using Methodology v1.7
Reviewed Sep 13, 2024 at 11:20 am
THIEAUDIO Monarch MKIII Picture
7.5
Neutral Sound
5.8
Commute/Travel
6.1
Sports/Fitness
5.7
Office
4.1
Wireless Gaming
6.2
Wired Gaming
2.4
Phone Calls

The THIEAUDIO Monarch MKIII are premium in-ear monitors (IEMs) positioned just below the Prestige LTD flagship IEMs in the company's current lineup. THIEAUDIO claims their revamped design for the Monarch MKIII means these buds produce a punchier sub-bass and louder output with lower distortion than their predecessor, the Monarch MKII. But have these IEMs done enough to reign over your ear canals? Read on to find out.

Our Verdict

7.5 Neutral Sound

The THIEAUDIO Monarch MKIII are good for neutral sound. Their bass and mid-range response are closely aligned with our target curve. Kick drums sound thumpy, and basslines have enough punch and warmth to cut through without ever overpowering the mix. Vocals and instruments are rendered accurately and with detail, so your favorite singers will sound just like themselves. Their treble range is more inconsistent and dulls sounds like sibilants and cymbals a little. Nonetheless, they deliver audio with remarkable consistency, so once you get a good fit you'll get the same sound with each wear. Their passive soundstage isn't very immersive, and the sound feels as if it's coming from inside your head, but that's to be expected from in-ears.

Pros
  • Remarkably consistent audio delivery.
  • Stable fit.
Cons
  • Poor passive soundstage.
5.8 Commute/Travel

The THIEAUDIO Monarch MKIII are a middling choice for commute and travel. They don't have active noise cancelling and, therefore, do a poor job of blocking out bassier sounds like the rumble of a plane engine. That said, they're able to passively block out a good amount of mid-range sounds like commuter chit-chat. They also leak very little audio, so anyone nearby won't be bothered by your audio. Their hard-shell carrying case is great for transporting the buds, but neither the buds nor the case have an IP rating, so be careful not to spill anything on them while in transit.

Pros
  • Great mid- and treble-range noise isolation.
  • Leak very little audio.
Cons
  • No controls on the buds or cable.
  • No IP rating against water or dust damage.
  • Poor at blocking out bass-range sounds like engine rumble.
6.1 Sports/Fitness

The THIEAUDIO Monarch MKIII are mediocre for sports and fitness use. On the plus side, they do a good job blocking out mid-range sounds like people talking in the gym, and they don't leak much sound, so anyone working out near you won't be bothered by your audio. On the other hand, they don't have any controls, so adjusting your music mid-step isn't easy, and they don't have an IP rating against water or dust damage, so these would be a poor choice for an outdoor run. And then there's the cable. While it's detachable, it's heavy and can easily catch on something, which could result in damage to the cable, connectors, or buds.

Pros
  • Great mid- and treble-range noise isolation.
  • Leak very little audio.
Cons
  • No controls on the buds or cable.
  • No IP rating against water or dust damage.
5.7 Office

The THIEAUDIO Monarch MKIII are sub-par for office use. They don't have an integrated microphone, so you'll need a standalone mic to take calls. Some might also find their in-ear fit a little uncomfortable for long days at the office. On the other hand, they do a good job blocking out mid- and treble-range sounds like office chatter and the whine of a nearby fan.

Pros
  • Great mid- and treble-range noise isolation.
Cons
  • No integrated microphone.
  • No controls on the buds or cable.
4.1 Wireless Gaming

The THIEAUDIO Monarch MKIII are wired-only headphones; you can't use them wirelessly.

6.2 Wired Gaming

The THIEAUDIO Monarch MKIII are mediocre gaming headphones. They're comfortable enough for shorter sessions, but since they're IEMs, they don't have the plush ear pads that traditional gaming headphones have. You probably won't want to wear these for marathon sessions. They also don't have a microphone, so you'll need a standalone mic to chat with fellow players. That said, other than the poor passive soundstage, which is to be expected from in-ears, these do a great job reproducing everything from explosions to dialogue, and their excellent imaging means you can accurately locate objects like footsteps in the stereo field.

Pros
  • Great mid- and treble-range noise isolation.
Cons
  • No integrated microphone.
2.4 Phone Calls

The THIEAUDIO Monarch MKIII don't have a microphone, so you'll have to bring your own mic if you want to use them for phone calls. If that's your plan, these do a good job blocking out the sounds like office chatter, so you can hear the person on the other end of the line.

  • 7.5 Neutral Sound
  • 5.8 Commute/Travel
  • 6.1 Sports/Fitness
  • 5.7 Office
  • 4.1 Wireless Gaming
  • 6.2 Wired Gaming
  • 2.4 Phone Calls
  1. Updated Sep 13, 2024: Review published.
  2. Updated Sep 10, 2024: Early access published.
  3. Updated Sep 04, 2024: Our testers have started testing this product.
  4. Updated Aug 26, 2024: The product has arrived in our lab, and our testers will start evaluating it soon.
  5. Updated Aug 07, 2024: We've purchased the product and are waiting for it to arrive in our lab.

Differences Between Sizes And Variants

The THIEAUDIO Monarch MKIII come in one variant, which has a black body and a black-and-white faceplate. However, if you're willing to pay a little more, you can order custom versions directly from the brand. Currently, they offer a total of six additional body colors and 14 faceplate styles for you to mix and match as you wish.

We expect our results to be valid for any of the customizable combinations on offer; see our model's label.

If you encounter another variant of these headphones, please let us know in the comments, and we'll update our review.

Compared To Other Headphones

The THIEAUDIO Monarch MKIII are premium in-ear monitors aimed at listeners who want portable high-fidelity audio reproduction. The MOONDROP Blessing 3 more closely follow our target curve, particularly in the treble region. If you like to hear the detail of each cymbal hit, the MOONDROP's voicing might be a better fit for you. On the other hand, if you prefer a smoother sound, the THIEAUDIO's recessed treble might be just the ticket. If that sounds like you but you can't stomach the THIEAUDIO's hefty price tag, the TRUTHEAR x Crinacle ZERO: RED are affordable IEMs that also have a warm sound.

If you want more high-quality sound headphones, check out our recommendations for the best audiophile headphones. You can also check out the best in-ear headphones, and the best headphones for music.

TRUTHEAR x Crinacle ZERO: RED

The TRUTHEAR x Crinacle ZERO: RED and the THIEAUDIO Monarch MKIII have similar sound profiles but very different prices. If you like a warmer, smoother sound, either of these pairs will suit you well. That said, the THIEAUDIO leak less audio and do a better job blocking out external noise, but they are significantly more expensive. Whether the improvements are worth the cost is up to you. 

MOONDROP Blessing 3

The MOONDROP Blessing 3 and the THIEAUDIO Monarch MKIII are IEMs with slightly different sound profiles. The THIEAUDIO have a slightly elevated bass range that lends a touch of extra thump and punch to kick drums. They also have a slightly recessed treble, which either enhances their smooth sound or makes them feel a little dull, depending on your preferences. The MOONDROP more closely follow our target curve, particularly in the treble region, so they are the better choice if you like to hear all the fine detail on a plucked string. The MOONDROP are also significantly cheaper than the THIEAUDIO.

TRUTHEAR x Crinacle ZERO

The THIEAUDIO Monarch MKIII and the TRUTHEAR x Crinacle ZERO are targeted at different segments of the IEM market. The THIEAUDIO are much more expensive than the TRUTHEAR and have a flatter bass range that reproduces your audio without adding much extra thump or punch. On the other hand, the cheaper TRUTHEAR have an excited sound profile that adds boom and rumble to 808 kick drums as well as sizzle to cymbals and high percussion. If you're a fan of bright trap triplet hi-hats, you might find the THIEAUDIO too dull.

Test Results

perceptual testing image
Design
Design
Style
Type In-ear
Enclosure Closed-Back
Wireless No
Transducer Hybrid

The THIEAUDIO Monarch MK3 are premium IEMs. The buds' bodies are made from premium resin. We tested the stock colorway version, which is mostly black apart from a swirly white pattern and some colorful, glittery highlights on the outer face of each bud. The THIEAUDIO brand name is printed on each bud in pale grey lettering. You can also order the buds with custom colors and faceplates directly from THIEAUDIO.

The contoured buds are designed to sit securely in each concha, supported by a copper-colored cable that wraps over your ears. Text on the inside of each bud helps you distinguish between the left and right one. They come with three sets of translucent white silicone ear tips and three sets of black foam tips that are color-coded by size.

7.0
Design
Comfort
Weight 0.1 lbs
Clamping Force
0 lbs

The THIEAUDIO Monarch MK3 have a decently comfortable fit. They come with small, medium, and large tips in both silicone and foam, so most people will have enough variety to find a fit and seal that works for them. However, if you've smaller ears, you might find that even the smallest tips are a bit painful. The outer part of the buds nuzzle easily and securely into your concha and distribute their own weight well. That said, they're quite heavy for IEMs, which may cause you some pain, and their heavy cable can create discomfort by pulling down on the buds.

0
Design
Controls
OS Compatibility
No Controls
Ease Of Use No Controls
Feedback No Controls
Call/Music Control No
Volume Control No
Microphone Control No
Channel Mixing
No
Noise Cancelling Control No
Talk-Through
No
Additional Controls No
8.3
Design
Portability
L 1.9" (4.8 cm)
W 3.7" (9.3 cm)
H 1.2" (3.0 cm)
Volume 8.17 in³ (133.92 cm³)
Transmitter Required No

The THIEAUDIO Monarch MK3 are very portable, like most in-ears. Still, it's worth noting that they're a bit heavier than many other IEMs.

8.0
Design
Case
Type Hard case
L 4.3" (10.9 cm)
W 5.4" (13.8 cm)
H 1.6" (4.0 cm)
Volume 36.72 in³ (601.68 cm³)

The THIEAUDIO Monarch MK3 come with a zip-up hard-shell case to store the buds and their accessories. The case is covered in a sturdy-feeling, thick fabric, and it'll do a good job protecting the buds from everyday damage like drops. That said, it doesn't have an IP certification, so be careful not to pack the case next to anything that might leak liquid. The case is lined with softer material so that the buds don't get scratched. There's also a pouch on the inside, which helps keep the accessories organized, and an elastic band secures the buds in place.

7.5
Design
Build Quality

The THIEAUDIO Monarch MK3 have a very good build quality. The bodies of the buds themselves are made from a high-quality resin that feels very robust, and the metal tips covering the speakers have a premium feel. Like many IEMs, the pins that connect the cable to the buds are very small and could get bent if not handled with care. Finally, the sturdy build quality of these headphones comes at the cost of added weight. The cable is heavy, and the buds weigh twice that of competitors like the MOONDROP Blessing 3.

7.5
Design
Stability

These IEMs have a good, stable fit. They are designed to fit comfortably in your concha, and their cable then hooks over your ears, which helps keep them in place. Even heavy headbanging to your favorite Haken tune won't dislodge these from your ears. However, their cable is quite heavy, and if you move around a lot, the weight of it could cause them to become dislodged, breaking their seal with your ears. You'll also want to take care not to snag the cable on anything.

Design
Headshots 1
Design
Headshots 2
Design
Top
Design
In The Box

  • THIEAUDIO Monarch MKIII headphones
  • Detachable cable (47 in/1.2 m)
  • 3x adapters (1/16 in/2.5 mm balanced, 1/8 in/3.5 mm single, and 11/64 in/4.4 mm balanced)
  • 3x pairs of foam tips (S, M, L)
  • 3x pairs of silicone tips (S, M, L)
  • Hard-shell carrying case
  • Microfiber rag

Sound
Sound
Sound Profile
Bass Amount
1.68 dB
Treble Amount
-1.82 dB

The THIEAUDIO Monarch MK3 have a well-balanced sound profile that is generally flat in the bass- and mid-ranges, before rolling off slightly in the treble range. That roll-off lends these IEMs a slightly warm, bass-heavy tonality, but they're never boomy or muddy. Kick drums feel thumpy, and the slight boost in the mid-bass ensures basslines have enough punch to cut through busy mixes. A peak in the low-treble can make vocals sound just a touch harsh at times, especially relative to the generally recessed treble range, but the overall sonic signature is more smooth than piercing.

9.7
Sound
Frequency Response Consistency
Avg. Std. Deviation
0.07 dB

The Monarch MK3 have outstanding frequency response consistency. In fact, they're among the best we've tested. Once you get a good fit and seal, these buds will deliver consistent audio with every wear.

Sound
Raw Frequency Response
9.1
Sound
Bass Accuracy
Std. Err.
1.32 dB
Low-Frequency Extension
10 Hz
Low-Bass
1.08 dB
Mid-Bass
1.93 dB
High-Bass
0.83 dB

The Monarch MK3 have superb bass accuracy. Their low- and mid-bass regions are practically razor-flat, with just a touch of boost in each to keep kick drums feeling thumpy and engaging. The high-bass is also fantastically well-balanced, with a slightly smaller boost that ensures basslines never become overly boomy. In songs like Bitter Melon by Cola, each note of the prominent melodic bassline is clear, and individual pitches don't jump out of the mix unnaturally.

9.0
Sound
Mid Accuracy
Std. Err.
1.35 dB
Low-Mid
-0.93 dB
Mid-Mid
-1.9 dB
High-Mid
0.01 dB

The Monarch MK3 have fantastic mid-range accuracy. The low-mids are virtually flat, but there's a small dip in the mid-mids that can make instruments feel a touch distant. The high-mids are superb: vocals in songs like Send My Love (To Your New Lover) by Adele sound clear and detailed without being harsh.

7.9
Sound
Treble Accuracy
Std. Err.
3.12 dB
Low-Treble
-1.49 dB
Mid-Treble
-4.28 dB
High-Treble
-5.53 dB

The Monarch MK3 have very good treble accuracy. If you like a warmer sound, these are a good choice because the entire treble range is de-emphasized. A dip in the low-treble means that sounds such as fingers plucking on nylon guitar strings lose a little detail and articulation. The entire mid-treble region is recessed which can make cymbals sound dull and sibilants like S and T a little lispy.

8.8
Sound
Peaks/Dips
Peaks
0.83 dB
Dips
0.69 dB

The Monarch MK3 have excellent peaks and dips performance, meaning they do an amazing job of following their own sound profile. A little boost between the mid- and high-bass regions adds a touch of warmth to basslines. A dip in the mid-mids and a peak across the high-mids and low treble means instruments can sound a touch distant or overly loud depending on their harmonic content. Finally, a big narrow peak in the low-treble and a couple of small dips in the mid-treble mean vocals can sound either a bit harsh or dull, depending on the pitch of the singer.

9.2
Sound
Imaging
Weighted Group Delay
0.14
Weighted Phase Mismatch
2.49
Weighted Amplitude Mismatch
0.65
Weighted Frequency Mismatch
0.62

The Monarch MK3 have outstanding imaging, and although we've only tested one product by the manufacturer, these results suggest superb quality control and ergonomics. Our unit's drivers are well-matched in group delay, amplitude, frequency, and phase response, so objects like voices are accurately placed in the stereo field, and the soundstage doesn't feel unnaturally tilted to the left or right. There's a small peak in the mid-range phase response, but it's not audible. Keep in mind that imaging varies between units, so these results are valid only for our unit.

0.6
Sound
Passive Soundstage
PRTF Accuracy (Std. Dev.)
N/A
PRTF Size (Avg.)
N/A
PRTF Distance
N/A
Openness
1.9
Acoustic Space Excitation
0.6

These IEMs have a bad passive soundstage performance, but that's to be expected from IEMs. Their in-ear design means audio can't interact with your outer ear like it can when you wear over-ears, meaning that they don't lend a sense of distance and width to the passive soundstage. Audio feels as though it's coming from inside your head and not two speakers in a room.

0
Sound
Virtual Soundstage
Head Modeling
No
Speaker Modeling
No
Room Ambience
No
Head Tracking
No
Virtual Surround
No App
7.5
Sound
Weighted Harmonic Distortion
WHD @ 90
0.237
WHD @ 100
0.209

These IEMs have good weighted harmonic distortion performance. Most frequencies fall within good limits. Even the broad peak from the mid-mid to mid-treble won't be audible to most listeners. Overall, these IEMs reproduce audio purely and cleanly.

Sound
Test Settings
Firmware
No Firmware
Power
Passive
Connection
Wired
Codec
PCM, 24-bit, 48kHz
EQ
No EQ
ANC
No ANC
Tip/Pad
Silicone (small)
Microphone
No Microphone

These are the settings used to test these headphones. Our results are only valid when used in this configuration.

Isolation
8.1
Isolation
Noise Isolation - Full Range
Noise Cancelling No
Overall Attenuation
-21.12 dB
Bass
-4.86 dB
Mid
-23.92 dB
Treble
-37.77 dB

These headphones have great full-range noise isolation, which they accomplish purely via passive isolation. Since they don't have ANC, they don't do a great job of blocking out bass-range sounds like the rumble of a bus engine. However, they do a very good job of isolating you from mid-range sounds like chatty coworkers and excel at blocking out trebly sounds like fan whine.

7.3
Isolation
Noise Isolation - Common Scenarios
Airplane Noise Attenuation
-16.97 dB
Airplane Noise Isolation Audio
Office Noise Attenuation
-17.47 dB
Office Noise Isolation Audio
Street Noise Attenuation
-20.02 dB
Street Noise Isolation Audio

These IEMs do a decent job of blocking out everyday sounds. They won't isolate you from the low-pitched rumble of a plane engine or a passing bus, but they'll greatly reduce the ambient sounds of an office, from your colleague's voice call to A/C whine. You also won't hear much in the way of pedestrian chit-chat when out on the street.

Isolation
Noise Isolation - Voice Handling
Female Voice 1
Male Voice 1
Female Voice 2
Male Voice 2
Isolation
ANC Wind Handling
ANC Wind Noise
N/A
9.5
Isolation
Leakage
Leakage Audio
Overall Leakage @ 1ft
24.33 dB

The leakage performance is remarkable. Even if you listen at loud volumes, audio that does escape is concentrated in the low- and mid-bass regions and will sound muffled to anyone nearby. Feel free to blast your favorite Sunn O))) tunes without fear of bothering people around you.

Microphone
Microphone
Microphone Style
Integrated
No
In-Line
No
Boom
No
Detachable Boom
No
Mic No
0
Microphone
Recording Quality
Recorded Speech
N/A
LFE
N/A
FR Std. Dev.
N/A
HFE
N/A
Weighted THD
N/A
Gain
N/A
0
Microphone
Noise Handling
SpNR
N/A
Noise Gate
No
Speech + Pink Noise Handling
N/A
Speech + Pink Noise Audio Sample N/A
Speech + Subway Noise Handling
N/A
Speech + Subway Noise Audio Sample N/A
Active Features
0
Active Features
Battery
Battery Type
No Battery
Continuous Battery Life
N/A
Additional Charges
N/A
Total Battery Life
N/A
Charge Time
N/A
Power-Saving Feature
No
Audio While Charging
No
Passive Playback
Passive Headphone
Charging Port None
0
Active Features
App Support
App Name No App
iOS No
Android No
macOS No
Windows No
Equalizer
No
ANC Control
No
Mic Control No
Room Effects
No
Playback Control
No
Button Mapping No
Surround Support
No
Connectivity
9.9
Connectivity
Wired Connection
Analog Audio
Yes
USB Audio
No
Detachable
Yes
Length
3.94 ft (1.20 m)
Connector
1/8" TRS
Latency - Analog
0.2 ms
Latency - USB
N/A
Recorded Latency
Recorded Latency Connection Analog

These IEMS come with a 47-in/1.2-m detachable cable. The smaller two-pin connectors plug into the buds, and the four-pin connector plugs into one of three adaptors: 1/16 in (2.5 mm) balanced, 1/8 in (3.5 mm) single, or 11/64 in (4.4 mm) balanced. You don't need a dedicated amp to drive these.

0
Connectivity
Bluetooth Connection
Bluetooth Version
N/A
Multi-Device Pairing
N/A
Quick Pair (Android)
N/A
Quick Pair (iOS)
N/A
Line Of Sight Range
N/A
Latency - SBC
N/A
Latency - aptX
N/A
Latency - aptX Adaptive (High Quality)
N/A
Latency - aptX Adaptive (Low Latency)
N/A
Latency - LDAC
N/A
Recorded Latency
N/A
Recorded Latency Codec N/A
AAC Support
N/A
0
Connectivity
Wireless Connection (Dongle)
Line Of Sight Range
N/A
Latency - Dongle
N/A
Recorded Latency
N/A
Connectivity
PC Compatibility
Analog
Audio Only
Wired USB
No
Non-BT Wireless
No

These buds don't have a built-in microphone, so if you connect them to your PC, you'll only receive audio.

Connectivity
PlayStation Compatibility
PS4 Analog
Audio Only
PS4 Wired USB
No
PS4 Non-BT Wireless
No
PS5 Analog
Audio Only
PS5 Wired USB
No
PS5 Non-BT Wireless
No

You can plug these into your PlayStation controller's AUX port, but they can only receive audio as they don't have a microphone.

Connectivity
Xbox Compatibility
Xbox One Analog
Audio Only
Xbox One Wired USB
No
Xbox One Non-BT Wireless
No
Xbox Series X|S Analog
Audio Only
Xbox Series X|S Wired USB
No
Xbox Series X|S Non-BT Wireless
No

You can receive audio from your Xbox by plugging these into an AUX port. They don't have a mic, so you'll need to add one if you plan to chat while you game.

0
Connectivity
Base/Dock
Type
No Base/Dock
USB Input
No
Line In
No
Line Out
No
Optical Input
No
RCA Input
No
Dock Charging
No
Power Supply
No Base/Dock