HeadphoneOverreview

DUNU Mortise

Everyone agrees it is comfortable, handsome and 'warm' — they just don't agree on what warm means.

28 sourcesUpdated
$430Typical US price

Score aggregates reviewer opinions across topics.

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DUNU Mortise

The short version

What to know.

A relaxed, midrange-first open-back that sources broadly agree is exceptionally comfortable, unusually well built and accessorised for the money, and tuned to be listened to for hours rather than analysed. Two independent rigs show why it reads as warm without any bass boost: the bass is flat to 20 Hz with no shelf, the 1–2 kHz region sits 4–7 dB below target, and the 3.5–7 kHz presence band runs 4–9 dB below it, so the low end and lower mids stand forward by default. Reviewers split on whether that adds up to a lush, HD 650-style coloration or a clean, modern near-neutral; on whether the stage is wide or intimate; and on whether the smooth delivery hides detail or quietly resolves more than the HD 6-series. A minority finds it needs more power than its 38 Ω / 98 dB rating implies, and a few hear the occasional sharp consonant on an otherwise dark headphone.

About this product

DUNU's second full-size headphone and its first with a dynamic driver (the 2025 Arashi is an open-back planar at roughly three times the price): a single 50 mm carbon-fibre-diaphragm driver, 38 Ω / 98 dB/mW, 325 g, North American black-walnut cups, a self-adjusting suspension headband with no cup swivel, and one black SKU. Ships with a single-crystal copper cable whose Q-Lock Mini plug swaps between 3.5 mm and 4.4 mm, plus a 6.35 mm adapter and a hard case. Sold at $429.99 since late March 2026.

DUNU built its reputation on in-ear monitors — the Zen, Luna, Falcon and DaVinci lines — and only reached full-size headphones in 2025 with the planar Arashi. The Mortise is the affordable follow-up: a 50 mm carbon-fibre dynamic driver in solid walnut cups, hung from a wire-and-strap suspension headband, sold for $429.99 into the most crowded shelf in headphones. The name is the joinery term; the Chinese character on the box, 卯, means the same thing.

Six months in, the big English-language outlets have not touched it, so the record is built from one full editorial review, a Chinese one, a retailer's shootout, five Head-Fi reviews, a lively Reddit and Head-Fi ownership trail, two video reviews and two independent measurement rigs. The verdicts are warm almost without exception; the argument is about what kind of warm, how big the stage is, and whether a headphone this easy on the ears is also resolving one.

A good fit for

  • Long, relaxed sessions where comfort and a fatigue-free treble matter more than analysis
  • Vocal, jazz, singer-songwriter and classic-rock listeners who want body and warmth without bloat
  • Anyone who finds the HD 600 too lean in the bass and wants a smoother, weightier alternative at the price
  • Buyers who value materials, a modular cable and a real case as part of the deal

Think twice if

  • You want a neutral or reference tuning, or upper-mid presence and bite on vocals and guitars
  • You are a treble-head chasing air, sparkle and cymbal shimmer
  • You need sub-bass slam for EDM or hip-hop — the extension is there but there is no shelf
  • You will only drive it from a phone or basic dongle and want it at its best
  • Isolation matters — it is fully open and leaks

The reviewer consensus

Agreement &
disagreement.

3 / 12topics divide opinion
9 Mostly agree3 Divided opinions

Common ground6

  • One of the most comfortable full-size headphones at the price: light, low clamp, no hotspots, multi-hour sessions
  • Build, cable and accessories well above the $430 norm — walnut cups, metal frame, swappable 3.5/4.4 plug, hard case
  • A warm, natural, full-bodied midrange that suits vocals, jazz, acoustic and classic rock

Points of contention6

  • Tonality — warm and lush (an HD 650 / 109 Pro relative) vs clean and near-neutral; the graph shows no bass boost, only recessed 1–2 kHz and 3.5–7 kHz
  • Soundstage — wide and spacious for the class vs intimate, front-row and depth-first
  • Detail — musical-first with merely adequate resolution vs quietly resolving above the HD 650 class

A closer listen.

12 topics · 3 divided
Left: criticalRight: positiveTighter lines: more agreement

Bass

Leans positiveMostly agree
Reviewer sentiment22 supporting sources
CriticalNeutralPositive

Band: opinion spread · Dot: weighted average

Most sources hear a full, punchy, mid-bass-forward low end — the thing several call its best feature — while a smaller group hears a polite, supportive bass with restrained sub-bass. Nearly everyone on both sides agrees the emphasis is mid-bass rather than sub-bass, that it stays clean of the mids, and that it never reaches basshead territory. The measurements complicate the language: there is no mid-bass hump and no roll-off.

“The bass is fuller than many listeners might expect from an open-back headphone. There is a clear mid-bass emphasis”

Goh Beng Yeow, Porta-Fi

“It's got a thick and heavy slam to it, more midbass than subbass focused.”

u/cl0ckw0rkaut0mat0n, r/headphones

“Overall, the bass performance is just average at best.”

DestinoAzell, Head-Fi showcase review

“EDM 계열에서는 다소 맥이 빠집니다. 이는 저역의 양감이 부족한 것이 가장 큰 영향을 줍니다.”

그리피스의꿈, Naver blog

Measured

Flat with no shelf on both rigs: 20 Hz sits within 0.5 dB (Elrics 711/KB50xx, five seatings) and 1.5 dB (Passion for Sound B&K 5128) of 500 Hz — 2–3 dB under a tilted diffuse-field target and about 5 dB under Harman 2018 in the bottom two octaves, but 7.8 dB above an HD 600 at 20 Hz on the same 711 rig and level with an HD 660S2 on the same 5128. 150–300 Hz is only 0.5–1.2 dB over target.

vs. listeners — Listeners describe a mid-bass emphasis and a restrained sub-bass; neither rig shows a mid-bass hump, and both show full extension. The 'punch' is the 1–2 kHz recession letting the upper bass and lower mids stand forward, and the 'restrained sub-bass' is the absence of a shelf rather than roll-off — which is also why the same graph reads as 'not warm' to graph-readers and 'very warm' to listeners.

Link to this topic

The hardware

Specifications.

Checked

Design

Type
Open-back
Drivers
1 × dynamic (carbon fiber diaphragm, N52 magnet, flexible surround suspension)
Housing
North American black walnut housing

Electrical

Impedance
38 Ω
Sensitivity
98 dB/mW≈ 112.2 dB/V
Frequency response
5 Hz – 40 kHz

Connection

Cable
Detachable, 1.5 m
Connector
3.5 mm
Plugs supplied
3.5 mm, 4.4 mm balancedmodular

Physical

Weight
325 g

Manufacturer-published figures, not measurements · from dunu-topsound.com.

Follow the evidence

Sources 28

1–6 of 28 sources

Read with context

Limitations & method.

As of

What to keep in mind 7

  1. A read of where the reviews land as of September 2026, six months after launch. None of the big English-language outlets has reviewed it yet, so much of the record is enthusiast reviews, forum owners and two non-English editorial tests — a first professional bench review would carry real weight here.

  2. Two units have been measured on two different rigs; they agree on the shape, but two is a small sample, and the one channel-balance wobble seen above 1 kHz on one of them could just as easily be seating as the unit.

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