Empire Ears ESR MKII vs THIEAUDIO Monarch MKIV
Introduction
The Empire Ears ESR MKII and THIEAUDIO Monarch MKIV are premium IEMs designed to deliver studio-accurate, high-resolution sound. Let's compare both models so you can find the best in-ear monitors for your listening preferences.
Not the right fit? Browse other In-Ear Monitors from Empire Ears and THIEAUDIO.
Empire Ears ESR MKII vs THIEAUDIO Monarch MKIV Price Comparison
The ESR MKII and Monarch MKIV sit at similar price points.
The ESR MKII comes in at $1,099.00.
The Monarch MKIV comes in at $1,149.00.
The ESR MKII costs slightly less than the Monarch MKIV. Let's dive deep into the specs, design, sound signatures, and features of both so you can get a better idea of what each IEM brings to the table.
The Empire Ears ESR MKII
The ESR MKII is Empire Ears' studio-reference IEM. It features a five-driver hybrid setup with three BA and two Electrostatic drivers. In terms of features, the ESR MKII packs SynX, EIVEC, and A.R.C technology for enhanced sound and reliability.
Empire Ears ESR MKII Features:
- 5-driver hybrid system with 3 BA + 2 electrostatic drivers
- 4-way synX crossover with EIVEC for electrostatic integration
- A.R.C. technology to reduce resonance for cleaner sound
- Brushed Silver aluminum faceplate with ergonomic resin shell
- Includes Alpha IV UPOCC Copper Litz cable
Empire Ears ESR MKII Specs:
Driver Configuration: 3x Balanced Armature Drivers + 2x Electrostatic Drivers
Frequency Response: 10Hz - 100kHz
Sensitivity: 111dB @ 1kHz, 1mW
Crossover: 4-Way synX Crossover Network
Impedance: 3.9 Ohms @ 1kHz
The THIEAUDIO Monarch MKIV
The THIEAUDIO Monarch MKIV is a flagship tribrid IEM designed to deliver both precision and versatility. With dual dynamic drivers, multiple balanced armatures, and electrostatic drivers, it offers a balanced sound signature that can be enhanced through its adjustable tuning switch. Built with a CNC-machined aluminum shell and paired with THIEAUDIO's modular cable system, the Monarch MKIV blends durability, comfort, and high-end performance without the flagship price tag.
THIEAUDIO Monarch MKIV Features:
- IMPACT² Dual Dynamic Drivers: Two 8mm dynamic drivers in an isobaric configuration deliver tight, powerful sub-bass with low distortion.
- Hybrid Driver Array: Six balanced armatures and two Sonion EST drivers extend clarity across mids and highs, with treble reaching up to 40kHz.
- Adjustable Tuning Switch: Choose between STANDARD mode for reference tuning or RUMBLE mode for +3dB sub-bass emphasis and added warmth.
- CNC Aluminum Shell: Crafted from aircraft-grade T6 aluminum for improved scratch resistance, durability, and comfort.
- Chocolate Modular Cable: Includes a high-quality cable with swappable 3.5mm and 4.4mm terminations for flexible source pairing.
THIEAUDIO Monarch MKIV Specs:
- Driver Configuration: 2 dynamic (IMPACT²) + 6 balanced armatures + 2 Sonion EST
- Frequency Response: 10Hz – 44kHz
- Sensitivity: ~100 dB/mW @1kHz
- Impedance: ~10Ω @1kHz
- Crossover: 4-way passive network
- Isolation: Passive noise isolation via ergonomic aluminum shell design
Design and Build Quality
The ESR MKII and Monarch MKIV are premium IEMs inside and out, boasting exceptional build quality, design, and ergonomics.
The ESR MKII keeps things professional yet simple. Its medical-grade resin shell is ergonomic and lightweight, ensuring long-term comfort, while the brushed aluminum faceplate adds a subtle touch of refinement. With A.R.C. applied inside the housing, internal resonances are minimized, making the sound cleaner and more accurate.
The THIEAUDIO Monarch MKIV carries a refined yet modern design. It features a precision CNC-machined aluminum shell that balances durability with long-wearing comfort. Its ergonomic shape ensures a secure fit while maintaining a premium feel in hand and ear. The faceplates feature subtle yet distinctive detailing, giving the MKIV a sleek, understated look compared to flashier flagships. THIEAUDIO offers two default faceplate designs: Stellashot, Kaleidoglow, alongside 14 custom options.
Completing the package is THIEAUDIO's upgraded Chocolate modular cable, a robust and flexible hybrid conductor that comes with interchangeable terminations for both 3.5mm and 4.4mm sources. This premium cable offers enhanced durability while complementing the Monarch MKIV's modern aesthetic.
Sound Signature
You're probably looking to see how these IEMs stack up on sound. We'll share our thoughts here, although keep in mind this information tends to be anecdotal and subjective.
ESR MKII Sound Signature
The ESR MKII is built around accuracy and balance, making it ideal for professionals or listeners who want to hear music exactly as it’s recorded.
Its bass is tight and controlled, never overpowering the mix. The midrange is clean and transparent, bringing out vocals and instruments with lifelike clarity - perfect for mixing or critical listening. The treble is extended yet smooth, revealing subtle details without harshness, ensuring long listening sessions stay fatigue-free. This combination gives you the confidence to make precise judgments on recordings while still enjoying natural musicality.
Monarch MKIV Sound Signature
The Monarch MKIV is tuned for balance, refinement, and versatility. Compared to the MKIII, it brings tighter bass control, a smoother treble, and a more natural midrange presentation.
The bass is delivered through its IMPACT² dual dynamic drivers, offering deep extension with clean, textured sub-bass and a punchy mid-bass that avoids bloat. In RUMBLE mode, the low-end gains extra weight and warmth, while STANDARD mode keeps the presentation accurate and controlled. The midrange is neutral and accurate, giving vocals a lifelike tone and instruments a clear, well-layered presence. Treble is airy and extended, with the EST drivers adding crisp detail and shimmer without sounding harsh.
The soundstage is wide and spacious, offering excellent separation and imaging that makes the presentation immersive and life-like.
Price and Value
At $1,099, the ESR MKII offers impressive value for professionals, studio engineers, or anyone who wants a reliable reference tool. Its neutral, accurate tuning gives you confidence in what you’re hearing, making it a cost-effective investment for critical work. The lightweight design and excellent isolation further enhance its practicality, delivering studio-grade performance without the premium price tag. For those who want precision sound and build, the ESR MKII delivers exactly that.
At $1,149, the Monarch MKIV delivers flagship-level performance without the flagship price tag. At that price, you’re getting a tribrid driver setup with dual dynamic subwoofers, Sonion EST treble drivers, and six precision balanced armatures - all tuned for versatility with STANDARD and RUMBLE modes. Add in the CNC-machined aluminum shell, modular Chocolate cable, and THIEAUDIO's crossover design, and the MKIV stands out as one of the best value IEMs in its class, offering near top-of-the-line sound at an accessible price.
Our Thoughts
Get the ESR MKII IEM if you're looking for a flat, accurate, and detailed sound for music production or mixing. The ESR MKII's reference-grade sound will help reveal subtle details in music making it a joy to use for mixing and mastering at home or in the studio.
The Monarch MKIV is designed for audiophiles who want reference-grade performance with the flexibility to dial in more bass when desired. It’s ideal for listeners who value balance, detail, and spacious presentation, but also enjoy the option of added low-end impact for modern genres. If you’re looking for a flagship-level tribrid IEM at around $1,000 that blends technical precision with versatility, the Monarch MKIV is the in-ear monitor to get.
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