ISN C4 English Review


With 4, It’s Enough




  • Construction.
  • Very low impedance.
  • Manageability and comfort.
  • Great balance between weight, thickness and rigidity/flexibility.




  • None worth mentioning.


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ISN does not forget its origins and continues to bring high quality cables to the market. On this occasion, it is a 4 strand cable. Each one of them is made up of 63 Single Crystal Copper cores. Months ago, I reviewed another cable of the same brand and also of copper, the C16. That one had 16 strands and was really thick. On this occasion, I believe that the reduction in the number of strands is very appropriate, in favour of better comfort, ease of storage and handling of the cable, with hardly any loss in quality.

As usual, the C4 can be chosen both in MMCX, and in 2pin 0.78mm. While its plug can be 2.5mm balanced, 3.5mm audio or 4.4mm balanced, covering a wide range of models.

Let’s see what other advantages this attractive copper cable, manufactured by ISN, offers.





  • Brand: ISN Audio
  • Model: C4
  • Material: Single Crystal Copper
  • Number of cores: 4 strands, each strand consists of 63 cores.
  • Connector: MMCX/2pin 0.78mm
  • Plug: 3.5mm audio/2.5mm balanced/4.4mm balanced, gold-plated
  • Cable length: 1.2M
  • Impedance Measurement: 0.45 Ω





Like many of the ISN products, the cable comes in a sealed transparent plastic box, measuring 122x78x38mm. Its colour is the classic ISN blue. The front is transparent, allowing you to see the plug, the two connectors and the cable. Both the plug and the connectors are embedded in a very thick and compact foam block. On the transparent window, there is a sticker with the brand logo.

On the back of the box there is another black sticker, where the model name, specifications and a description of the cable’s virtues can be found.

Inside the box there is simply the cable, there are no more accessories.

The packaging is simple and effective. There is no box or carrying bag. There is also no velcro tape to pick it up.


Construction and Design


The cable is composed of 4 strands of 63 cores each, giving a total of 252 cores. Each strand is covered with transparent plastic and all of them are intertwined with each other. The cores are made of high purity single crystal copper and have a very bright colour, which gives an idea of their quality, proving that their purity is real. Each strand is approximately 1.2mm thick

In my case, the cable analysed has MMCX connectors and a 3.5mm Audio plug. This plug is gold-plated and has a black and cylindrical sheath, which has a holographic pattern, alternating black and grey. The name of the brand (ISN Hi-Fi) can be read on the case, inscribed in white letters on a completely black background. The diameter of the case is 8.5 mm and its length is almost 25 mm. The dividing piece is very similar, but this time its pattern is larger and occupies almost the entire piece. It has the same diameter but a shorter length, which does not reach 21mm. The pin is a flexible black plastic piece, which has two holes, one for each channel. It is small, 4.5mm long. Finally, the MMCX connectors are gold plated and their sleeves are matching with the rest of the parts of the cable, since they are black cylinders, with the same drawn pattern. Their dimensions are 13mm long by 6.1mm in diameter. Each connector has a circular notch painted in red or blue, to identify the channel, right and left, respectively.

Both the weight and the thickness of the cable are very balanced. It is just right to express a great quality, but without being over-dimensioned or thick. It has a good relationship between rigidity and flexibility, which gives it a very good handling and a very low tendency to get tangled. The weight is hardly noticeable and the absence of rigid guides on the ear, allows it to be used completely freely. The MMCX connectors feel very high quality and their fit is firm and durable, without being susceptible to poor connection due to movement or use. I should point out that I have used this cable daily for several weeks, both at work and for light sport, without feeling any disconnection in the MMCX connectors.

The measured impedance is really low, giving a value of 0.45 Ω on the multimeter, exactly half of what the Tin HiFi T4 cable measures (0.9 Ω).

With all these virtues, it is impossible to highlight anything negative in the construction, handling or comfort of this ISN C4 cable. Therefore, its evaluation in this section can only be excellent.





In order to highlight the virtues of the ISN C4, I have focused on a few IEMS whose sound I am quite familiar with. But, I would like to highlight the test performed with the Tin HiFi T4. From the beginning, I noticed that their cable was not entirely appropriate, basically because of its rigidity. Luckily, I was able to replace it with the shiny copper of the ISN C4. And I must say that the differences are clearly noticeable. The impedance of the cable has been halved to begin with. There are no differences in the volume, but you can perceive a better definition in the lower zone, even a greater depth and expansion of the bass, gaining in distance and in the representation of the different planes. The volatility of the sound has increased, improving transparency, achieving a darker and cleaner background. Voices have also received a little boost, especially in their expressiveness, where details and nuances are presented with greater immediacy and boldness, with a point of greater capacity in the resolution and definition of the sound. In the high zone, it is already known that copper can modulate the brightness and in this case, I cannot deny it. However, this smoothness does not translate into a loss of clarity or detail, but rather into a slight attenuation in the first highs, which can mean a gain in control, in those IEMS that have a somewhat more problematic transition to the highs. This is not the case in T4, but it has helped in other more critical IEMS in this respect. Despite this, the treble does not lose strength, nor does it sparkle, and because the separation is greater, the treble is perceived as finer and more delicate, with a more realistic and focused representation.

The scene deserves a special mention, since the conjunction of the previous improvements, is directly translated into the recreation of the musical image. There is more global air and the space has a clear tendency to a different order, more ethereal and free, but without losing the musicality, nor falling into an unreal or forced representation. It is just a matter of giving the IEMS greater freedom, transparency and three-dimensionality, when producing the sound, which is appreciated from the first notes.





Sometimes, simplifying things offers benefits. This time, 4 strands are enough to create a large cable. Although, in reality, they are not so few. Together they form 252 cores.  ISN C4 has the perfect balance between thickness, comfort, quality and price. Not to mention its low impedance and, of course, the improvement it brings to the sound.

The C4 avoid an exaggerated thickness, but without losing the brightness of its copper, nor its connectors. They focus on providing what a listener demands from a cable, basically, a better user experience, combining better manageability, with enhanced sound. No more, no less.



Sources and Headphones Used During the Analysis


  • Tin HiFi T4
  • ISN RAmbo II
  • ISN H40
  • Ourart QJ21
  • BGVP ArtMagic VG4
  • EarMen TR-Amp
  • Qudelix-5K
  • xDuoo XP-2Pro
  • Tempotec Variations V1-A + Earmen Sparrow