COZOY D2

Disclaimer

The D2 has been sent by COZOY, I really appreciate their support to bring you content about their products.

My video review:

You can buy them directly their website:

COZOY D2 - Normal price $55 USD

Pros

• Punchy and dynamic bass

• Great quality cable

• "Airy" treble without being harsh

• Comfortable and lightweight

Cons

• Some lack of bass extension

• A sound signature very consistent with its predecessor

Accessories

7 pairs of eartips

1 carrying case

1 modular 0.78mm 2 pin cable

1 pair of D2 IEM

Technical specifications:

Brand name: COZOY

Model name: D2

Transducer Type: 10mm graphene diaphragm driver + 6mm beryllium driver

Frequency response: 10 - 50Khz

Sensitivity: 102dB SPL/mV

Connector: 0.78mm 2-pin

Amplification & Power hungry

These are very easy to drive. If you plan to use them with a dongle DAC, my top recommendation would be a DAC with an AKM chip, followed by Cirrus Logic as second choice, and Sabre as third choice.

I recommend this because AKM DACs generally have a slightly smoother top end with less prominent treble, Cirrus Logic tends to sound neutral and balanced, while Sabre chips can lean excessively clean/bright, which further highlights the D2's treble.

The 4.4mm balanced connection isn't strictly necessary here; the 3.5mm output provides more than enough headroom, and I noticed no obvious difference switching to balanced.

Bass

The bass is fast, clean, and exhibits very good separation between mid-bass punch and sub-bass extension.

I wouldn't say the dedicated 6mm sub-bass driver stands out prominently, but if you like to EQ, the drivers respond remarkably well. There is no distortion unless you push the low end excessively; the maximum boost I could apply while maintaining cleanliness was around 3 to 4 dB with a wide Q-factor across the bass and sub-bass regions.

Midrange

The midrange is another area showing clear improvement over the D1. It maintains the same signature style—very forward so that vocals take center stage—with slightly lower overall energy and zero distortion compared to the D1.

Vocals can sometimes feel slightly thin even in the mid register, primarily due to the lack of body in the lower midrange and mid-bass, but overall vocal presentation across different genres is very competent.

Treble

The treble retains a relatively pronounced peak in the upper mids/lower treble, around 8 to 10 kHz, providing more "air" and openness than the D1.

For genres featuring fast hi-hats or heavily distorted acoustic and electric guitars, it can get somewhat harsh or peaky.

It doesn't sound sibilant to my ears, but if you are treble-sensitive, these IEMs could cause listening fatigue fairly quickly.

Sounds like another IEM?

The D2's tuning is a very consistent evolution of their first model's signature. As mentioned earlier, I feel a slight low-end boost would have rounded it out. The closest IEM I own in terms of presentation is the NF ACOUS NM25; personally, I prefer the bass and treble on the D2, while the NM25's midrange feels slightly cleaner, albeit a bit less forward.

Tested on:

Galaxy s10e

iPhone 12 & 16

Fosi K7

Fiio KA13

Arturia Audiofuse

Macbook Air M1

Design

The design is very similar to the D1, featuring an all-black resin shell with an attractive faceplate design that looks quite good in person.

They are slightly larger than the D1, yet remain lightweight and remarkably comfortable.

It retains the 0.78mm 2-pin connector and a metal nozzle with a fully integrated mesh filter, which shows good build quality.

The cable is a massive step up from the previous model—it is a braided type that feels light and resists tangling. I didn't experience any ear fatigue or discomfort even after several hours of continuous listening, despite the ear hook coating looking somewhat thin.

It includes interchangeable 3.5mm and 4.4mm plugs, which in my opinion should be the standard for IEMs in this price range.

Lastly, I didn't detect any noticeable change in sound when testing other IEMs with this cable; there is no perceived boost or roll-off in bass or treble.

Sound - How I perceive it?

As for the sound signature of the D2, I would describe it as having controlled bass with midrange and treble that are more forward than "normal."

This brings me to my first gripe with this IEM: given how good the bass quality actually is, Cozoy decided to keep it somewhat subdued. A couple more decibels in the bass and sub-bass region would have made it practically perfect for my taste.

Soundstage & Imaging

The soundstage is wide and precise, largely aided by the treble extension. It offers an open presentation, particularly with instruments like hi-hats or guitars that are hard-panned to either side, delivering a convincing stereo effect.

There is some sense of depth, though modest; it is most noticeable on backing vocals and ad-libs with reverb/delay placed further back in the mix.

For gaming, I definitely recommend them: they are easy to drive, and the wide soundstage is very advantageous for competitive titles.

Conclusion

The COZOY D2 represents an upgrade across the board compared to their debut model. It maintains a sound signature very consistent with its predecessor, which is by no means a negative—especially if you already enjoyed the D1 and know what to expect.

It offers better resolution across the entire frequency spectrum, a vastly improved cable, solid build quality, and great ergonomics. However, if you are someone who cannot tolerate a brighter sound, I cannot recommend them.

They are an easy recommendation for gaming if that is your primary use case, as that treble-forward presentation lends itself well to competitive audio cues.

Thanks so much to COZOY for providing this unit for review.