Wired IEMs
Cozoy D2
81Outstanding
$55
Full review dataCozoy D2 vs HiFiMAN RE400i: which should you buy?
On aggregated review scores the Cozoy D2 comes out ahead with a HearWiki score of 81. The full breakdown - sub-scores, specs and what reviewers actually said - is below.
Our pick: Cozoy D2 - Outstanding overall at around $55.
Wired IEMs
HiFiMAN RE400i
57Average
$64
Full review dataScore breakdown
Each axis is a 0–10 blend of what reviewers scored, not a lab measurement.
Cozoy D2 leads on 4 of 4 measures.
- Cozoy D2
- HiFiMAN RE400i
HearWiki score
81
57
Sound
8.5
6.5
Value
9.0
3.5
Price (USD)
$55
$64
Generation & platform
The scores rank quality. This is the other question: is the newer one actually newer technology, or the same platform in a new shell?
Same generation
The Cozoy D2 is 2 years newer, but it is the same generation of hardware: nothing in the radio, the codecs or the noise cancelling separates them. Nothing separates them on convenience features either, so the choice comes down to tuning and price.
- D220262 yr newer
- RE400i2024
Specifications
D2RE400i
- Type
- Wired IEMs
- Wired IEMs
- Price (USD)
- $55
- $64
- HearWiki score
- 81
- 57
- Released
- 2026
- 2024
- Availability
- Sold new
- Discontinued
- Driver
- 2DD
- 8.5 mm driver
- Driver type
- dynamic
- -
- Driver configuration
- 2DD
- -
- Driver size
- -
- 8.5 mm
- Drivers per side
- 2
- 1
- Frequency response
- -
- 15 Hz - 22 kHz
- Impedance
- 20 Ω
- 32 Ω
- Sensitivity
- -
- 102 dB/mW
- Active noise cancelling
- -
- No
- ANC type
- -
- none
- Transparency mode
- -
- No
- Companion app
- -
- No
- Custom EQ
- -
- No
- Wear detection
- -
- No
- Controls
- -
- buttons
- Voice assistant
- -
- No
- Weight
- -
- 13.5 g
- USB-C
- -
- No
- Connector
- 2-pin 0.78 mm
- 3.5 mm
- Microphones
- -
- 1
What reviewers said
Cozoy D2
The Cozoy D2 is a budget-friendly wired IEM that pairs a 6 mm beryllium driver with a 10 mm graphene-composite driver for a dual-dynamic setup. It offers a flexible connection via a 2-pin 0.78 mm cable that includes swappable 3.5 mm and 4.4 mm plugs, catering to both standard and balanced sources. With a 20-ohm impedance, it's easy to drive from most devices.
- Pro:Dual-driver hybrid design for detailed sound
- Pro:Interchangeable 3.5 mm and 4.4 mm plugs
- Pro:Low impedance (20 ohms) for easy pairing
- Con:No active noise cancellation
- Con:Wired only, limiting portability
- Con:Budget build may not suit all users
HiFiMAN RE400i
The HiFiMAN RE400i is a lightweight, wired IEM that delivers a smooth, balanced, and detailed sound signature, making it a strong value for budget-conscious listeners who prioritize clarity over bass punch. Its compact fit and comfortable design are complemented by a decent accessory set, though the build quality—especially the cable—is a notable weak point. Best suited for acoustic, classical, or critical listening, it lacks modern extras like app support or a robust remote.
- Pro:Accurate, detailed midrange and treble
- Pro:Neutral, non-fatiguing tuning
- Pro:Very lightweight and comfortable
- Con:Bass is restrained and lacks impact
- Con:Cable is thin and feels fragile
- Con:No app support or advanced features
Summaries are AI-condensed and paraphrased from published reviews and specs - not original hands-on testing. More on our method.
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