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16 Sep 2020

Review: Ollo Audio S4X headphones

producer Review: Ollo Audio S4X headphones

Ollo Audio is a relatively new brand from Slovenia, the owner named Rok has been active in the music industry for years as a band member and mixing engineer. When mixing with a deadline, Rok had to work through the night, his wife and children were already in bed. The drums of the mix woke them up at least 5 times, so the search for a solution began - mixing on headphones.

Rok ran into the problem that he could not perceive the sound through his headphones if he can with studio monitors. After a long search for a good solution, Rok started working with speakers and headphones. Then Ollo Audio was born, a creative and innovative brand that wants to change the existing headphone market.

Earlier we looked at the Ollo Audio S4R, but today we take a look at a new model called the S4X.

Read on below for the review.

What is Ollo Audio?

We have of course already explained a few things about the origin of Ollo Audio in the intro of this article. But Ollo Audio really has an interesting approach and provides a breath of fresh air in the headphone market.

Every headphone is tested and measured. A piece of paper of this is included as can be seen in the photo above. You can view the frequency response of your individual headphone on this. There will be a lot of testing and measurement on offer at Ollo, watch the video below for more information about testing and measuring the headphones - very interesting if you ask us!

The Ollo Audio S4X

The Ollo Audio S4X is ideal for a number of situations such as: mixing, reference sound, working at home, mastering and of course listening to music at home. Because the headphones have an open design (so that the ear cups are open) you also hear the space around you, you don't want closed headphones during mixing. You want to mix spatially and not isolate yourself, causing you to make the wrong choices in a mix.

The S4X have been extensively tested to ensure that they sound as flat as possible and offer a perfect outcome as a frame of reference during mixing. The S4X was created based on feedback Ollo received from the S4 model. An even more natural frequency response, more room for your ears and a larger headband ring.

The S4X comes with a high-quality 2 meter cable which is very nice and a bag to store the headphones! Another detail is that Ollo sells parts separately, which of course extends the lifespan considerably.

View all specifications of the Ollo Audio S4X below.

  • Speaker size 50mm
  • Frequency range 20-22kHz reference response
  • SPL / sensetivity 108dB / 1vrms @ 1Khz 32ohm
  • Impedance 32ohm, smart devices ready
  • Ear cups outer diameter 90mm
  • Cable termination Detachable 2 meters long Y 2.5mm mini jack
  • Connector 3.5mm jack with an adapter to 6.3mm jack
  • Weight 350g
  • Magnet type Neodymium
  • Transducer type Dynamic
  • Coil 2 layered
  • Membrane material PET 25h
  • Matched speakers Handpicked pairs
  • Warranty 5 years limited warranty
  • The build quality

Well enough background information, how did they eventually build the product? You can see that it is not machine and factory work - which is positive. Ollo Audio really went looking for the right materials and makes them itself. This is reflected in the complete finish, which is very neat.

The headphones feel very sturdy, the choice of materials is correct and the walnut wooden ear cups are very beautiful. In addition, the material for the ear cup that lies on your ears is very soft and made of acoustic foam in combination with velor - very soft!

All in all, a very nice product that immediately shows that it is something special. Small sidenote: the previous version vibrated a lot when you touch the metal band - this is no longer the case with this model.


Perhaps the biggest plus in our eyes, the comfort is incredibly good. We have now tested dozens of headphones from consumer to professional models - but the S4X is unprecedented in this price range in terms of comfort. It is incredibly good and will certainly not irritate quickly. They have this very well done at Ollo Audio!

The sound quality

Sound is of course very important to achieve the right result as a mixing engineer. Ollo Audio naturally offers a high level of comfort, but also an excellent flat response in terms of frequencies. The sound does not sound colored, but also very powerful.

In any case, they are the go-to headphones for us during mixing!


All in all, Ollo Audio is doing very well to create a very nice series of headphones for an affordable price! The build and sound quality is very good. High comfort, well-tested audio ensure that you have a reliable reference as a producer in the studio.

A very nice brand which may be less obvious, but that makes it interesting!

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