Empire Ears ESR MKII vs 64Audio Aspire 4
Introduction
The Empire Ears ESR MKII and 64Audio Aspire 4 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 Aspire 4 Price Comparison
The ESR MKII and Aspire 4 sit at the same price point.
The ESR MKII comes in at $1,099.00.
The Aspire 4 comes in at $799.99.
The ESR MKII costs around $300 more than the Aspire 4. 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 Aspire 4
The 64Audio Aspire 4 is a mid-range hybrid IEM designed to bring 64Audio’s core technologies to a more accessible price point. It combines a dynamic driver and balanced armatures with Apex Core isolation and a precision waveguide for a clean, fatigue-free listening experience.
Aspire 4 Features:
- Hybrid 4-driver design: 1 dynamic driver for low frequencies, 2 balanced armatures for mids, and 1 balanced armature for highs
- Apex Core technology for reduced ear fatigue and improved natural isolation
- Custom acoustic waveguide on the high driver for improved clarity
- Lightweight molded ABS shell with stainless steel nozzle for durability and comfort
- Detachable 48″ black IPX cable with right-angled 3.5 mm jack
Aspire 4 Specs:
Driver configuration: 1 DD + 2 BA (mids) + 1 BA (highs)
Frequency Response: 20 Hz – 18 kHz
Sensitivity: 104 dB/mW @ 1 kHz
Impedance: 11 Ω @ 1 kHz
Isolation: ~−20 dB (with Apex Core)
Cable: IPX detachable, 48″ length, 3.5 mm termination
Design and Build Quality
The ESR MKII and Aspire 4 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 Aspire 4 features a lightweight matte black ABS shell paired with a glossy black faceplate that carries the 64Audio logo for a simple yet refined look. A stainless steel nozzle ensures durability and a secure fit for ear tips, while integrated Apex Core venting reduces air pressure for lasting comfort. The detachable black IPX cable with a right-angled 3.5 mm jack adds portability and reliability, making the Aspire 4 both practical and stylish for daily use.
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.
Aspire 4 Sound Signature
The Aspire 4 delivers a balanced, musical presentation with a focus on clarity and accuracy from bass to treble.
The dynamic driver produces a punchy and well-textured bass, while the dual balanced armatures handle the mids with natural detail and separation. The dedicated high BA with acoustic waveguide ensures smooth treble extension without harshness, making vocals and instruments sound crisp yet fatigue-free. Overall, the Aspire 4 offers a versatile tuning suited for both casual listening and professional audio monitoring.
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.
The Aspire 4 is positioned as 64Audio’s entry-level hybrid IEM, offering their signature technologies at a more accessible price point. At $799.99, the Aspire 4 features a 4-driver hybrid setup, Apex Core isolation, a stainless steel nozzle, and a detachable IPX cable system, along with a full accessory kit. Despite using simpler materials compared to flagship 64Audio models, the Aspire 4 combines a clean, detailed, and accurate sound with the durability and comfort for extended listening sessions at home, onstage, or in the studio.
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 Aspire 4 is the IEM to get if you want a balanced-sounding hybrid monitor that brings 64Audio’s core technologies into a more affordable package. The Aspire 4 is a great fit for enthusiasts and pros seeking clear mids, controlled bass, and smooth treble in a lightweight, durable design. With its versatile tuning, fatigue-free sound thanks to Apex Core, and a reliable build with practical accessories, the Aspire 4 is an excellent entry point into the 64Audio lineup.
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