Triple-dynamic-driver IEM with acoustic crossover design

The Moondrop Harmon is a triple-dynamic-driver IEM featuring three full-sized 10mm drivers—one for mid-treble and two for bass—paired with a patented four-cavity acoustic crossover system. It houses each driver in its own precisely engineered chamber, enabling clear phase alignment, extended frequency response, and low distortion. Backed by simulation-grade acoustic modeling and expert hand-tuning, the Harmon delivers deeply layered imaging, precise tone, and dynamic control in a remarkably compact form factor.

Three 10mm drivers

Instead of stacking armatures or mixing driver types, the Harmon relies on three large 10mm dynamic drivers—one for mids and highs, two for lows. Each driver lives in its own resonant cavity, precisely engineered to handle a specific frequency band. The result is phase-consistent crossover, rich harmonic blending, and cohesive imaging.

Mid-treble driver with glass-dome diaphragm

The mid-treble driver uses a one-micron-thin glass dome in a flexible suspension system, giving it a unique mix of stiffness and damping. That means less distortion, stronger dynamics, and treble extension that doesn’t get brittle or shouty. Its dual-magnet, triple-conductor motor system pushes a high-efficiency OFC voice coil for detailed playback.

Dual bass drivers with horizontal opposition

Moondrop’s horizontally-opposed bass driver configuration cancels out unwanted mechanical vibration while doubling down on dynamic output. Each 10mm driver includes an internal N52 magnet, lightweight CCAW coil, and flexible diaphragm tuned for punchiness. The result is low end that’s clean, fast, and tight even with dense compositions. 

Four-cavity coaxial crossover design

At the heart of the Harmon is a four-cavity frequency crossover system. Instead of relying solely on electronic filters, the Harmon’s tuning leans on acoustic cavity design and pathing to split and shape frequency the bands. This crossover strategy offers control over phase alignment, minimizing smearing and helping all three drivers work together. 

VDSF target tuning and real-world refinement

Moondrop’s VDSF tuning target is built on B&K HRTF data. The Harmon hits it with impressive accuracy—then goes a step further with subjective tuning to match real-ear coupling and listener preference. You get lifelike imaging, smooth timbre, and a tonal balance that works well across genres.

Full-band phase consistency

Phase alignment gets harder as you add more drivers. But thanks to its coaxial architecture and physical crossover design, the Harmon keeps full-band phase highly consistent. That means better imaging, more realistic transients, and less fatigue during long sessions.

Ultra-low distortion across the board

Even under pressure, the Harmon stays clean. At 94dB SPL, total harmonic distortion across the full frequency range stays under 0.1%—a level that most multi-driver IEMs can’t match.

Braided cable, dual plug system

The Harmon ships with a high-quality braided cable and both 3.5mm single-ended and 4.4mm balanced plugs. The connectors are easy to swap—just align the arrow indicators and match your output source without changing cables or adapters. 

Product highlights

• Triple 10mm dynamic drivers in coaxial formation
  
• Glass-dome mid-treble driver with composite magnetic circuit
  
• Dual horizontally-opposed bass drivers with N52 magnets
  
• Four-cavity coaxial acoustic crossover system
  
• VDSF target tuning with real-ear refinement
  
• THD ≤ 0.1% at 94dB SPL
  
• High phase consistency across full frequency band
  
• B&K 5128C HATS tuned and measured
  
• Precision DLP 3D printed shells from HeyGears
  
• 3.5mm and 4.4mm plugs included with braided cable
  

Specs

• Model: Harmon In-Ear Monitors (Coaxial Four-Cavity Frequency Crossover / Three Dynamic Drivers)
  
• Driver configuration:
  
  • 1x 10mm Glass Dome Composite Diaphragm Mid-Treble Driver
    
  • 2x 10mm Paper Cone Composite Diaphragm Bass Drivers (H.O.D.D.D.U.S.)
    
• Impedance: 19Ω ±15% (@1kHz)
  
• Sensitivity: 114dB/Vrms (@1kHz)
  
• Frequency response: 10Hz–60kHz
  
• Effective frequency range: 20Hz–20kHz (IEC60318-4, -3dB)
  
• THD: ≤0.1% (@1kHz, 94dB)
  
• Connectors: 0.78mm recessed 2-pin
  
• Cable plugs: 3.5mm single-ended and 4.4mm balanced
  

What’s included

• Moondrop Harmon IEMs
  
• Braided cable with 0.78mm 2-pin connectors
  
• 3.5mm single-ended plug
  
• 4.4mm balanced plug
  
• Carrying case
  
• Ear tips (multiple sizes)
  
• Documentation and warranty card