KOYO: A Masterpiece of Acoustic Engineering and Natural Artistry

Jomo Audio is proud to announce the global debut of Koyo, a cost-effective tri-brid in-ear monitor (IEM) that harmonizes cutting-edge material science with traditional craftsmanship. Named after the vibrant autumnal foliage, Koyo represents a peak in acoustic performance and aesthetic soul.

1. The "Living" Shell: Hand-Polished Stabilized Wood & Stainless Steel

The KOYO’s housing is a testament to our commitment to quality, featuring a striking combination of stabilized wood and a precision-brushed stainless steel frame.

What truly sets the wood shell apart is our uncompromising approach to surface finish: we use no glossy lacquer whatsoever. Instead, the surface is treated with a meticulous polishing process that reveals the wood’s natural grain and texture in their purest form.

This unpainted, polished finish does more than just look beautiful—it enhances the acoustic performance. Preserving the wood’s natural porous structure, it allows for a more natural, organic reverb effect within the acoustic cavity. The sound interacts with the wood in its most authentic state, resulting in a warmer, more natural tonal balance and a more immersive sound stage.

As with all natural materials, the stabilized wood will develop a unique and beautiful patina over time, deepening in color and character with each use. Each pair of KOYO becomes a truly unique piece, evolving with its owner to tell a story of time and enjoyment.

2. FlowMax Open-Back Design: Precision Engineered for Balance

At the core of KOYO’s acoustic design is the FlowMax open-back panel, crafted from CNC-machined gold-plated brass. This open architecture optimizes air flow and sound dispersion, creating a more natural sound stage that avoids the feeling of claustrophobia often associated with closed-back designs.

The gold-plated brass finish not only adds a touch of elegance but also ensures excellent signal conduction and heat dissipation. Every edge and curve is precision-engineered to work in harmony with the internal driver configuration, delivering a balanced and detailed sound signature that excels across all music genres.

3. Tri-Brid Acoustic Architecture: Full Spectrum Fidelity

KOYO features a sophisticated tri-brid driver configuration, combining the strengths of three different driver technologies to deliver a seamless and full-range sound signature:

· 1 Dynamic Driver (DD): Delivers deep, impactful, and textured bass response.

· 3 Balanced Armature Drivers (BA): Provide exceptional clarity, detail retrieval, and precise imaging in the mid and high frequencies.

· 1 Planar Magnetic Driver: Offers smooth, extended highs and sparkles with splendid airiness.

4. Graphene-Infused Resin: Elevated Clarity and Control

To further enhance acoustic performance, the KOYO incorporates a proprietary AC2X Asymetrical Co-axial Acoustic Chamber, constructed from graphene-infused 3D-printed resin. This innovative dual-design combines the unique properties of graphene with a thoughtfully engineered cavity structure to redefine IEM acoustic performance.

The AC2X Asymetrical Co-axial Acoustic Chamber is engineered with a key innovation: it couples the bass and ultra-high frequency drivers into the same cavity while leveraging asymmetric design principles to eliminate cross-frequency interference. By isolating these extreme frequency ranges from one another, the chamber ensures that the low-end warmth and ultra-high frequency crispness do not "bleed" into each other—preventing muddiness in the bass and harshness in the highs, and preserving the integrity of each frequency band. This separation of extreme frequencies is critical to maintaining a clean, balanced sound signature, as it avoids the common issue of frequency overlap that can distort the overall audio experience.

Beyond frequency isolation, the AC2X chamber is specifically optimized to provide the optimal operating environment for the balanced armature (BA) drivers. The asymmetrical co-axial structure minimizes internal resonance and acoustic interference, while the graphene-infused resin enhances the cavity’s rigidity and damping properties—key factors in ensuring BA drivers can deliver their signature precision and detail retrieval without distortion. The graphene reinforcement significantly increases structural rigidity, minimizing unwanted micro-vibrations, while its excellent damping performance absorbs residual vibrations to create a clean, noise-free acoustic environment.

The combined effect of the AC2X chamber and graphene-infused resin is a cleaner, more accurate sound with lower distortion, tighter bass control, enhanced clarity across the entire frequency spectrum, and a more natural tonal balance. This advanced acoustic architecture ensures that the tri-brid driver system can perform at its absolute best, realizing the full potential of the design—all at a mid-range price point that makes this level of acoustic engineering accessible to more music lovers.

5. Oil-Immersed Copper-Silver Cable: Pure Signal Transmission

The KOYO is equipped with a high-performance oil-infused coaxial cable, featuring a core constructed from single-crystal copper (OCC Copper) and single-crystal silver (OCC Silver) conductors.

This premium cable design offers several key advantages:

· Reduced Signal Loss: The oil-immersed construction minimizes signal resistance and capacitance, ensuring that the audio signal is transmitted with minimal degradation.

· Superior Conductivity: The combination of single-crystal copper and silver conductors provides an optimal balance between warm, natural midrange (copper) and crisp, detailed highs (silver).

· Reduced Interference: The coaxial structure effectively shields against external electromagnetic interference (EMI), ensuring a clean and noise-free signal path.

Every nuance of the music is preserved and delivered with pinpoint accuracy, from the subtlest of background details to the most dynamic crescendos.

KOYO represents our vision of making high-end audio performance accessible to all, We’ve combined rare materials, cutting-edge engineering, and rigorous tuning to create an IEM that delivers sound quality and build far beyond its price point. It’s an audio experience that connects you more deeply with your music.

While Koyo incorporates materials and technologies often found in ultra-high-end "boutique" products, it is positioned as a highly competitive, high-value solution. It is designed for listeners who demand top-tier acoustic performance and artisanal craftsmanship without the typical flagship premium.

Specifications

• l Stabilized Maple hardwood shell, waxed
• l Stainless steel frame with gold-plated brass skeletoned faceplate
• l FlowMax Open-back grille
• l 1 x 10mm custom silk diaphragm dynamic driver
• l 1 x 6mm nano planar magnetic super tweeter
• l 3 x precision balanced armature drivers
• l 3D-printed AC2X (Asymmetrical Co-Axial Acoustic Chamber)
• l Graphene-infused resin
• l 4-channel C.S.U. crossover circuit
• l 0.78mm gold-plated inner-claw 2Pins female connector
• l Frequency response: 20Hz - 45KHz
• l Impedance: 12.5 ohms @ 1KHz, 0.5Vrms
• l Sensitivity: 113.8dB @ 1KHz, 0.5Vrms
• l Oil-infused OCC Copper-Silver Blend Cable, 4.4mm termination