



Jomo Audio Koyo Review: An Autumnal Work of Art with a Massive Soundstage
Pros:
- Truly breathtaking hand-polished stabilized maple wood shells with gold-milled faceplates.
- Class-leading, expansive soundstage width that creates an enveloping, out-of-head listening experience.
- Deep, borderline basshead sub-bass rumble with excellent air movement and dynamic slam.
- Organic, fatigue-free treble presentation with zero harshness or sibilance.
- Smooth, warm midrange that delivers natural vocal timbre and great layering.
Cons:
- Stock oil-infused cable is overly thick, cumbersome, and lacks a chin slider.
- Included leather puck case is far too cramped to store the IEMs and stock cable easily.
- Organic wood shell finish raises slight durability concerns for users with excessively sweaty ears.
Welcome back, audiophiles! It’s me, your boy Joe, back again with another review! Today we are taking a look at a release from the boutique audio house Jomo Audio: the Jomo Audio Koyo (retailing for around $950 USD). Sitting right near kilobuck territory, my expectations for this set were sky-high out of the gate. Named after the vibrant Japanese autumn foliage, the Koyo packs a 5-driver tri-brid acoustic architecture inside a hand-polished stabilized maple wood housing. Let's see if this beauty has the sonic muscle to back up its breathtaking looks!
Disclaimer
A huge shout-out and thanks to the Audio Geek India group for providing this review unit! As always, all thoughts, impressions, and opinions are entirely my own with zero biases whatsoever.
Pricing & Specifications
- Price: ~$950 USD
- Driver Architecture (5-Driver Tri-Brid): 1x 10mm Custom Silk Diaphragm Dynamic Driver (Lows) + 3x Precision Balanced Armature Drivers (Mids/Highs) + 1x 6mm Nano Planar Magnetic Super Tweeter (Ultra-Highs)
- Impedance / Sensitivity: 12.5 Ω @ 1kHz / 113.8 dB @ 1kHz
- Connectors: 0.78mm 2-Pin (4.4mm Balanced stock termination)
Gear Used for Review & Drivability
The Koyo is relatively efficient on paper and runs smoothly without requiring nuclear-grade power:
- HiBy R8 II
- Gustard X16 / H16 Desktop Stack
- Tanchjim Space 2 (Portable Dongle)
- Music Source: Apple Music Lossless
While it isn't strictly power-hungry, scaling up to desktop-class power like the Gustard stack stretches its soundstage dimensions even wider!
Design, Build, and Accessories
- The Shells (Pure Artistry): The shells are the prettiest IEM shells I have ever seen, period. The waxed, stabilized natural maple hardwood paired with the precision-milled gold leaf brass faceplate and stainless steel skeleton frame is utterly breathtaking.
- Wood Maintenance & Sweaty Ears Concern: Jomo even includes dedicated wood conditioning oil in the package to keep the natural wood hydrated and pristine. My only minor concern is for users with sweaty ears during long sessions. I am not entirely sure how well the untreated organic wood porous structure handles long-term moisture and sweat exposure over years of use.
- The Stock Cable & Cable Rolling: The stock oil-infused OCC copper-silver blend cable is far too thick and bulky for my liking. Worse yet, it completely lacks a chin slider! Because I am not a fan of thick oil-infused cables in general, I did some cable rolling:
- Effect Audio Dionysus: Looked stunning and added great refinement.
- Verus Audio Lavender: A phenomenal aesthetic and sonic synergy that improved ergonomics drastically.
- The Carrying Case: The bundled leather case is simply too small. Trying to pack the chunky Koyo shells alongside that thick stock cable is an extreme squeeze. A roomier case would have gone a long way at $950
Sound Impressions
Sonically, the Jomo Audio Koyo presents a versatile all-rounder sound signature crowned by one of the widest, most expansive soundstages I have ever heard in an in-ear monitor.
- Soundstage & Staging: Absolutely massive. The presentation feels like the music is playing from a generous distance around your head, creating a grand, concert-like atmosphere.
- Bass: The low-end reaches borderline basshead levels! The 10mm silk dynamic driver pushes impressive air movement with a deep, authoritative sub-bass rumble that keeps energetic tracks tactile.
- Mids: The midrange is clean, lush, and leans pleasantly towards warm. The organic acoustic damping of the wooden chamber works absolute magic here, rendering vocal timbre with rich, natural realism.
- Treble: Handled by the balanced armatures and planar super tweeter, the top end is remarkably smooth, organic, and cohesive. There are zero sharp peaks, sibilance, or fatiguing spikes anywhere in the upper register.
Song Impressions
- "Dame Mais" by Tropkillaz, Rincon Sapiência & Clau: The bassline on this track is deep, powerful, and rumble-worthy. The Koyo tackles the low end with zero qualms and it hits deep and strong without bleeding into the lower mids. The midrange leans warm, which is right up my alley. The mixed male and female vocals are rendered with pristine separation, completely free of congestion.
- "Tłoki" (feat. Gibbs) by Kukon: The baseline here is super deep and rumbling, and the Koyo renders that subterranean weight effortlessly. Snares and hi-hats hit with clean precision without crossing into sharpness. The male vocals are presented cleanly with great body; while they don't jump "forward" in the mix, it feels true to the track's master rather than an IEM flaw.
Overall Impressions
Rating: 4.5 / 5
The Jomo Audio Koyo is a sonic and visual triumph. It combines heirloom-level wooden artistry with an expansive soundstage, borderline basshead low-end rumble, and a fatigue-free, natural tonality. It loses half a star purely because the bundled package feels incomplete for $950 as the stock cable is overly thick with no chin slider, and the leather case is far too cramped. But if you are willing to roll your own cable and case, the Koyo stands as one of the finest, most natural-sounding all-rounders in the sub-kilobuck tier!