Dekoni x HIFIMAN Cobalt review featured image

Dekoni x HIFIMAN Cobalt Review

In this feature, James reviews the Dekoni x HIFIMAN Cobalt, which is a collaborative set of closed-back headphones with a new 45mm dynamic driver. It is priced at $399.99.

Disclaimer: This sample was sent to me in exchange for our honest opinion. Headfonics is an independent website with no affiliate links or status. I thank Dekoni Audio for their support.

Click here to read more about the Dekoni products we have previously covered on Headfonics.

Note, that this article follows our latest scoring guidelines which you can read here.

Dekoni x HIFIMAN Cobalt review featured image
Dekoni x HIFIMAN Cobalt Review
Overall, the Dekoni x HIFIMAN Cobalt is lightweight, rugged, and a very comfortable set of dynamic driver headphones. It has a versatile and clean tuning that suits a wide range of musical genres, delivering vocals with great clarity.
Sound Quality
Comfort & Isolation
Slide here to add your score on the gear!28 Votes
Decent dynamics
Lightweight design
Excellent & additional earpads
Plastic construction
Limited bass power
Lack of carrying pouch
Award Score

In this feature, I will be reviewing the Dekoni x HIFIMAN Cobalt Closed-Back Dynamic Headphones.

This is a special collaboration that combines the expertise of Dekoni’s premium earpads with HIFIMAN’s lightweight headphone architecture, featuring a carbon-coated diaphragm in its driver and priced at $399.

What could an earpad manufacturing company do to the sound of a headphone with two sets of pads?  Read on for my full assessment of this headphone’s performance to find out how.

Dekoni x HIFIMAN Cobalt sheepskin pads

Tech Highlights

The Dekoni x HIFIMAN Cobalt Closed-Back headphones use a 45mm dynamic driver so this is not your typical planar driver from HIFIMAN.

It’s something completely new from HIFIMAN and picked specifically by Dekoni to provide what they feel is a contrasting sound to the Dekoni Blue planar headphones reviewed by Louis previously on this website.

As such it’s a fairly easy headphone to drive at just 16 ohms and 101 dB /mW and for most people it will work fairly well out of both a portable source and desktop headphone amplifier.


The new driver uses a carbon-coated diaphragm for the driver unit, and fine-tuning is achieved by the placement of carbon coating on different parts of the membrane.

The rest of the design is planned around this basis, with Dekoni placing different materials behind the driver in the earcup to alter the overall response.

Dekoni x HIFIMAN Cobalt extra earpads


The next step was the pads since every aspect of an earcup may affect the output curve and performance.

Testing internally, Dekoni’s staff experimented with various materials e.g. high-density memory foams of different styles, and eventually on the Fenestrated Sheepskin pads known for being comfortable and with high breathability.

The earpad’s memory foam is also heat-activated. The experience is similar to pillows or seating pads, so I can assure you from my experience with the headphones to date that the fit and comfort levels from the Cobalt are very good.

Earpad Choices

If you manage to obtain one of the first 1000 units, you will also receive an extra set of Elite Velour pads. These pads not only change the output tonality of the Cobalt headphones but also have a distinct, premium appearance and feel to the touch.

This offers a unique experience as switching to these pads results in an alternative tuning preferred by Dekoni’s engineer.

However, it should be noted that removing and installing the alternative set of pads may require some skills and care, it is quite easy once you figure out how the clip-on design works.

Dekoni x HIFIMAN Cobalt design


The extremely light Cobalt headphones are built around HIFIMAN’s framework. So, the headband structure is very similar to the Edition XS or the Deva Pro, just with a different set of closed-back plastic earcups in matte, navy blue color.

I like the subtle coloring and the finish feels very smooth. The stepped design also looks great and practically turns the design into an oval shape which enhances the fit.

The overall design is minimalistic and rigid in structure, you can twist it quite a bit, and seems like it is ready for some daily abuse. On both sides of the earcups, there is a socket for detachable cables terminated with 3.5mm connectors, and there are plenty of upgrade cables that fit.

Dekoni x HIFIMAN Cobalt headband insignia

Comfort & Isolation

Although HIFIMAN didn’t advertise it much, the frame for the Cobalt allows for movement in different angles, making it very easy to achieve a good fit and very evenly spread the weight, promoting isolation at the same time. The thick headband may look a bit bulky but is very comfortable on the head or the neck.

The earpads, with their oval shape, are also large enough to prevent contact with the sides of the ears, ensuring a comfortable experience.

Particularly when using the sheepskin pads, which have a premium feel to the touch, the presence of pores allows for some airflow exchange, preventing the headphones from feeling too stuffy on a hot day.

Isolation from the Cobalt on the other hand is satisfactory. The plastic material or the earpads with pores allows a bit of the ambiance to pass through but once the music is on, I consider the outside noise not too audible.

Dekoni x HIFIMAN Cobalt cable socket

Stock Cable

The Cobalt headphones come with a rather standard-looking cable with a thick gauge and over-molded parts that make it look and feel quite sturdy.

The cable is terminated with 3.5mm plugs on both sides of the cups as well as the connector to the source, and it is compatible with quite some aftermarket cables, or the stock cable of other headphones.

I swapped on the Moondrop Venus stock cable and found out that it tilts to the treble and sounds slightly veiled, also not as expansive, and dynamic as the stock cable on the Cobalt.

I tried using another balanced Copper cable as well and received better results, but I still regard the stock cable as a very good pairing that yields stronger dynamics and resolving power from the Cobalt even on a 3.5mm connection.

Packaging & Accessories

The Cobalt comes in a well-protected cardboard box and inside you will find the headphone units and an extra pair of earpads, which are only available for the first 1000 pairs.

There is a cable binder coming inside the package so you can use it to tie it up when putting in a travelling case or pouch.

It would be nicer if Dekoni could consider supplying a small bag at least, as the Cobalt is something you can bring along for your commute or travel.

Dekoni x HIFIMAN Cobalt paired FiiO Q15

Sound Impressions

I allowed a week of run-in for the Cobalt before any sound impressions were made. I also used the stock Sheepskin pads mainly for the impression, which I prefer for its fuller bass response and its more premium texture.


The Cobalt is tested with multiple sources to simulate different usage scenarios, including dongles and DAPs with smaller outputs like the Shanling M3X.

Generally, the Cobalt is tuned to be expansive, smooth, and dynamic sounding with an M-shaped, forgiving tuning that puts a small stress on vocal clarity, which is great for streaming content.

With a more powerful source, you can hear the resolution being boosted and the treble getting more aggressive yet remaining peak-free. The supplied Elite Velour pads will give the treble a small boost and get more exciting and analytical in tone.


Initially, I was skeptical about the bass response of the Cobalt due to its plastic construction which may sometimes lead to unwanted vibrations and resonance.

However, upon receiving it, I discovered that the tuning is more focused on the upper frequencies while maintaining satisfactory body, resulting in a vocal performer with an M-shaped tuning, with a spacious headroom rendered. The bass also manages to go down quite deep and has an airy punch.

While listening outdoors on TIDAL at maximum quality, the sub-bass of the Cobalt may be somewhat reserved but still discernible. The high-pass effect allows the higher frequencies to shine through with enhanced clarity.

Clarity is further strengthened with the Elite Velour earpads which have a stronger high-pass effect to my ears, exhibiting a stronger level of control and enhanced bass transients.

On the other hand, the mid-bass has sufficient weight to not sound hollowed out, and the drivers respond well when paired with more powerful DAPs to sound fuller in body and more resolving.

Voices are perceptibly more focused and possess a notable presence with satisfactory intensity in the low end and more intensity in the upper bass frequencies.


The Cobalt midrange frequency is spotlighted and is smoothly rendered with adequate body and sufficient energy in the upper frequencies to stand out and sound clearly defined.

Higher-pitched voices penetrate well and have stronger air, especially with the Elite Velour pads. There is good clarity around the 5kHz area which gives the vocalist some energy. This helps to brighten up streamed content and gaming sound FX.

Using the Sheepskin pads the Cobalt sounds more mellow while maintaining some density, which favors darker voices and tunes from the 80’s. It also highlights the harmonics while keeping the pace light and joyful.

The tuning works well outdoors to deliver the vocal line without sharpness, though you may find acoustic instruments presented slightly analytical and flat like from studio monitors as the mid-bass area is less energized.


The Cobalt treble has good clarity and is swiftly articulated from the lifted upper mids area, with sufficient detailing and good nuance in the revealed harmonics.

It sounds quite extended and has a gentle roll-off that preserves air in the upper treble range, with just a bit of sparkle to add to the liveliness without getting out of control.

The treble intensity and tuning work well with EDM and J/Kpop, nudging the electronic elements within, as well as for woodwind instruments. When paired with less powerful devices, it achieves a good balance in tone as well as good clarity.


The Cobalt excels in staging, partially due to its extended sub-bass and reserved bass, as well as its impressive extension that creates spacious headroom.

As a result, instruments sound more spread out, while vocals, especially lighter voices, take a front position and are well-separated.

The Cobalt also offers good depth perception, and its moderately responsive membrane, particularly when paired with less powerful devices, effectively reveals bass details and airy qualities.

When it comes to acoustic instruments and pianos, there is adequate detail, although the impact may feel slightly subdued, and the holographic effect is not as pronounced. Pairing the Cobalt with warmer sources will give it a better balance if you focus more on the instruments.

Click on page 2 below for my recommended pairings and selected comparisons.

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