Empire Ears ESR MKII vs 64Audio U4s
Introduction
The Empire Ears ESR MKII and 64Audio U4s 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 64Audio.
Empire Ears ESR MKII vs 64Audio U4s Price Comparison
The ESR MKII and U4s sit at the same price point.
The ESR MKII comes in at $1,099.00.
The U4s comes in at $1,099.00.
The ESR MKII and U4s cost the same. 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 64Audio U4s
The 64Audio U4s is an entry-level U-Series IEM packed with four hybrid drivers and innovative technologies like Tia, Apex, and Linear Impedance design for a versatile listening experience in any genre.
64Audio U4s Features:
- One dynamic driver for bass response.
- Two balanced armature drivers for midrange and treble.
- One tia™ high-frequency driver for extended treble.
- Apex™ modules (mX, m15, m20) for adjustable noise isolation.
- LID™ technology for consistent sound across devices.
64Audio U4s Specs:
Driver Configuration: 1x Dynamic Driver, 2x Balanced Armatures, 1x Tia high-frequency Driver
Frequency Response: 5Hz – 22kHz
Sensitivity: 105 dB/mW @ 1kHz
Impedance: 11Ω @ 1kHz
Crossover: Integrated 4-way passive crossover
Shell: Slate blue aluminum housing with Muonionalusta meteorite-inspired faceplates
Design and Build Quality
The ESR MKII and U4s are premium IEMs, boasting exceptional build quality, design, and ergonomics.
The ESR MKII keeps things professional and understated. 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 64Audio U4s goes for different direction in terms of design and materials compared to the Empire Ears Triton. Whereas the Triton uses medical-grade resin for its shells, the U4s features a lightweight aluminum build for enhanced durability and feel. Design details include unique slate blue shell color paired with Muonionalusta meteorite-inspired faceplates. Like other 64Audio U-series IEMs, the U4s features 64audio's half-moon shell shape with Apex Modules located at the bottom of the front faceplates.
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.
U4s Sound Signature
The U4s is a versatile in-ear monitor with tuning that offers satisfying playback in any genre. Its overall sound is balanced and musical, characterized by tight powerful bass, natural vocals and instrumentals, and an ultra-detailed treble.
In real-world music listening, the U4s' tuning translates to impactful kick drums, exciting vocals, and a vast soundstage with good separation between instruments and sounds. Speaking of soundstage, sounds are easy to locate with the U4s, and the overall size of the sound image is wide and spacious, which makes for an immersive listening experience.
Price and Value
At $1,099, the ESR MKII is a strong value proposition for professionals and purists. Its hybrid BA + EST design, resonance-free housing, and neutral tuning make it a cost-efficient reference monitor without unnecessary frills. The ESR MKII features high-quality resin shells with brushed aluminum faceplates, alongside a premium braided cable for enhanced sound and aesthetics.
At $1,099, the U4s offers impressive value, combining a solid build, high-tech features, and a versatile sound that will suit a wide range of listeners. The Slate Blue aluminum shells offer a lightweight and robust feel, while technologies like Tia, Apex, and LID offer enhanced sound and comfort. Like the Volur, the U4s features swappable Apex Modules that allow you to fine tune sound and noise isolation to your preferences.
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 U4s offer an exceptional blend of sound, build, and features. Bass, midrange, and treble are excellent on the U4s, offering an exciting, energetic, and detailed sound that works great for any genre. The build quality is top-notch, and the technologies and features you get are identical to higher-end 64Audio offerings. Get the U4s if you want a taste of high-resolution sound without breaking the bank.
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