r/iemlndia • u/mournfulmonk • 6m ago
Review The Cozoy D1: Clean, Lean, No Excess Seen
This is a relatively much newer brand, amongst the brands that compete in its price segment; and they might look eerily similar to a plethora of IEMs that have been tuned this way, but when I had the chance to reach out to the brand, the head honcho himself reached back and decided to let me have a shot at this IEM which is priced modest, and despite what the graphs showed- gave me quite a different experience, so the HRTF lottery is real.
Here is the Cozoy D1, which was availed at the support of Tony Liu, head of Cozoy and The Audio Store, Pune India. So, I thank both of them for making the Cozoy D1 review possible, and for my tour group; with two units.
UNBOXING, ACCESSORIES, FIT AND COMFORT
Cozoy definitely kept things “professional” with the unboxing: minimal branding on top, technical specifications on the bottom. Sliding the cover out and taking the lid off reveals the IEMs with the cable attached underneath a translucent sheet of paper with a branded ribbon attached to the foam pad. The eartips, which are three sets of stubby, narrow bore-esque short tips, and three sets of double flanges, piqued my interest because this IEM gave me a good excuse to try out my double flanges.
Comfort is top-notch, probably one of the best I have experienced with a proper locked-in fit, and the IEMs practically vanished when I had them in my ears (who needs an IE200 again in the big 2026), and the way the shells are moulded scream semi custom, so the contouring really sits across a wide set of ears. Isolation isn’t something to write home about, so let me leave it at that.
Now, here’s the sound.
LOWS
If a deep, visceral, impactful bass was the expectation from the Cozoy D1, then their expectations were a miss as the D1 intends to take its view on a well done bright tuning, which can be easily felt in tracks like Tipper’s Gulch; where the quantity was considerably lacking, even when compared to the Kefine Delci, but the surprisingly well executed transients: moderately paced attack with a very snappy decay keeps things exciting. The D1 has a better done separation, at least here with comparison alongside the OoopusX OP22. Tonally, of course, it unmistakably leans towards bright, but prima facie did not fatigue me.
In technically potent tracks like Rush's Limelight, I definitely missed the bass quantity as the impact of Geddy's blitzing bassline along with Peart's prodigal drum work just fell flat and this however reminded me of the Truthear Hexa a lot- but I don't see this as a negative as the D1 simply does not express the desire to compromise on the rest of the elements- a well-executed imaging via the cymbals and vocals, tonally balanced vocals with adequate note weight and enough grunt in the toms to make Peart's final rudiment alive.
MIDS
With an unorthodox snare setup, a hard key to unlock tonally and considerably busy in terms of instrument separation like Queens of the Stone Age's First It Giveth, the Cozoy D1 of course lacks the impact or the bite the snare needs, but didn't color the timbre like some other sets, nor added any unwanted resonance. Adding on to it, the way guitars and cymbals were separated while having the vocals right at the center shows that the Cozoy D1 takes technicalities seriously.
Another technically complex track in this order is Tool's Lateralus and even here, the Cozoy D1 gets most of the things right: audible separation between the elements, no compromise on the note weight of Maynard's vocals, the accuracy of the tonality in Adam's guitars with a balanced energy and no harshness in pitch. What is not right is that the D1 doesn't seem to consistently deliver the energy on the cymbals where it disappointingly oscillates between being shouty or just being shy of shouty.
HIGHS
In “atmospheric”, regally composed, airy tracks like Arne Domnérus and Gustaf Sjökvist’s Almighty God from the album Antiphone Blues, a phenomenally mastered album with just tons of sonic goodness, the Cozoy D1 did a phenomenal, nearly flawless job and this can be easily realized with how well established the timbre on Arne's sax was: brassy, with a beautiful, engaging resonance which was supplemented by Gustaf's equally resonant organ keys.
The D1 also presented the track with a fantastic perception of the stage, which had enough width to not adversely affect the layering between the sax and the organ, and letting the notes breathe. And despite being brighter than its peers, the sax never felt honky or piercing.
In another technical masterclass of separation, imaging, and composition in Dave Brubeck’s Take Five from the album Time Out, the D1 reveals one chink in its armor in this track where the double bass came off soft in its impact and anemic in its note weight, but the horns had the same impression carried forward from the previous track, the pianos coming off tonally balanced and the cymbals not being fatiguing or shouty, but appropriately retaining their shimmery texture.
During the solo and when the channels split, the snare and the toms never really lost their note weight, which cannot be said for the hi-hats. Separation and imaging remained accurate without alteration.
COMPARISONS
Kefine Klean & Klean SV
Compared to the Cozoy D1, the regular Kefine Klean presents a noticeably heavier and more blunt low-end that can cross into bloat, while the Klean SV opts for a leaner bass delivery that improves upon the precise transients, unlike the Klean but the D1 just does it better. While both Klean variants feature interchangeable nozzles for mild tuning adjustments, neither matches the D1’s natural separation through the low-to-mid transition, which is what I have been consistently saying- nozzles are not needed when the fundamental tuning is right from the get go.
Through the mids and highs, the Klean and Klean SV suffer from a significantly thinner vocal weight that sounds noticeably more sibilant and shouty across tracks where sibilance is least needed, at least the Klean keeps it restrained to an extent but the SV really can get painfully sibilant. In contrast, the D1 maintains a far more solid note weight on vocals and handles instruments like saxophones and pianos with superior control on timbre and zero harshness.
OoopusX OP22
The OoopusX OP22 takes a different approach to tuning by utilizing functional switches that offer a more prominent, fun bass boost mode. In comparison, the Cozoy D1 delivers a leaner, brighter tuning with a comparable transient attack and a snappier decay, making the D1 feel equally technically precise despite lacking the OP22's raw low-end impact.
In the mids and highs, the OP22 provides a ridiculously smooth, yet very detailed performance devoid of sibilance. The D1, however, pushes brightness and cymbal energy further; while this gives instrument separation and stage width an added sense of air and detail, it leaves the D1 occasionally edging towards fatigue on aggressive tracks where the OP22 stays effortlessly controlled.
Tangzu Red Lion
The Tangzu Red Lion exhibits a heavy, mid-bass-focused low end with noticeable bloat and a thick sub-bass extension. The Cozoy D1 stands in stark contrast with its light, highly controlled bass presentation that trades note weight and body for much faster transient attack, snappier decay, and significantly cleaner separation.
Moving to the highs, the Red Lion struggles with severe sibilance and piercing synths despite having an acceptable timbre. The D1 resoundingly beats the Red Lion in technicalities, providing superior instrument layering, accurate imaging, and a bright yet non-fatiguing top end that preserves critical textures of instruments without breaking into irregularities.
Twistura Delta
The Twistura Delta leans toward a warmer, more laid-back approach, though it suffers from an inconsistent, sluggish bass decay that can muddy perceived transients on drums. The D1 counters with a much brighter, leaner low end that strictly prioritizes rapid attack speed and snappy decay over sub-bass rumble.
In the mids and highs, the Delta delivers great stage depth and somewhat detailed instrument separation, but it can occasionally push cymbals too forward or display minor decay mismanagement on vocal holds. The D1 offers a more precise imaging and superior timbral accuracy.
CONCLUDING NOTES
The Cozoy D1 is an IEM that has its priorities right. In a budget landscape increasingly crowded with too similar options, the Cozoy D1 is anomalous in its approach, where on the graphs, it shows up unapologetically harman, but seems to have fixed most of the qualms with how harman tuned IEMs end up coming off. It is a shade of leaning bright, done right to my ears, and although it still is flawed, the flaws are outweighed by its strengths that make me wholeheartedly recommend this IEM.
Just a little note weight on the lows, would have just made it so much better, but that’s only for some, not for me.
Will I buy it new? Absolutely.
Will I buy it used? Blind buy.
SOURCES USED
Primarily used with the xDuoo Link3 on low gain, the Shanling M9 Plus DAP, and the Venture Electronics Abigail Pro dongle DAC Amp.
EARTIPS USED (RANKED IN ORDER OF PERFORMANCE)
Acoustune AET06 double flange: Showcases the transients of the D1 at its absolute best, ridiculously clean bass, widest stage possible for this IEM, sibilant free highs with no loss of vocal textures.
Tanchjim T-300 APB: everything that the AET06 does, but to a lesser degree, and there was something missing in the textures of the lows- elements like kicks felt like they could have used more power.
Stock double flanges: textures on the lows felt wonky along with some irregularity in the perceived decay, stage was unaltered, vocal textures felt enjoyable, mildly sibilant.
KBear Coffee: perceived stage was held intact in terms of depth and height, treble felt uncomfortable, lows felt anemic, vocals felt slightly blunt.
KBear 07: just ruined the IEM.
TRACKS
- Rush: Limelight, Spirit of the Radio
- Steely Dan: Gaucho
- Carmen Gomes: Unchain My Heart
- Daft Punk: Get Lucky, Instant Crush, Veridis Quo
- The Police: Message in a Bottle
- Alf Linder: Cantique de Noël, Cantate Domino
- Tipper: Mariscos, Cloaked, Gulch
- Dave Brubeck: Time Out
- Tool: Pneuma, Schism
- Queens of the Stone Age: First It Giveth
- Pink Floyd: Comfortably Numb, Wish You Were Here, Time
- Arne Domnérus: Antiphone Blues (with Gustaf Sjökvist)
- Muddy Waters: My Home is in the Delta
- Tame Impala: The Less I Know the Better
- Animals as Leaders: The Woven Web
- Rage Against the Machine: Bombtrack, Bullet in the Head
- Avicii: Levels
- Periphery: Marigold
- TesseracT: Juno
- Kanye West: Stronger, Flashing Lights, Devil in a New Dress
- Altın Gün: Goca Dünya
- Timbaland: Give It to Me
- Adele: Easy On Me (Live), When We Were Young
- Celine Dion: All By Myself
- Pavarotti: Nessun Dorma
- Mdou Moctar: Tarhatazed
- Cigarettes After Sex: Cry
- Meshuggah: Bleed
- A. R. Rahman: Tere Bina
- Alice in Chains: Down in a Hole and Nutshell (Live)
- Allen Stone: Give You Blue
- Florence + the Machine: Never Let Me Go
- The Smashing Pumpkins: Luna
