August 12, 2021 Off By Editor

OLLO Audio – headphones are creating a sensational impression on audio professionals and audio consumers alike.


OLLO Audio is a company independently born out of Slovenia from very humble beginnings between two audio enthusiasts – Rok Gulič & Mitja Sajovic. A company based on a desire to provide high-quality headphone design for mixing, mastering, and recording purposes. Includes both studios and home use.

The visual design of OLLO headphones is very appealing with a modern fashionable approach,

they look unique with a hybrid postmodernist aesthetic

This has been an instant attraction for many and continues to gravitate to audio pros and music consumers alike. Their current headphone range is already receiving a great response across the audio industry from pro engineers, studio producers, and mastering engineers, and I was very keen and happy to get my hands on a pair to test and further use for my music production and mixing.

Rather than an exhausting technical spec review, I wanted to dive into the experience of the S4X.

Why are studio headphones important?

First of all, and something to look at later in this review – OLLO headphones are not purely for the professional studio/musician market. They are more versatile than pro use and carry an important factor.

For studio production use – There are many reasons why having a good reliable pair of headphones is almost paramount in modern recording and mixing. An obvious is an alternative to your studio monitors as a different listening experience. Remember the old test your mix in the car method? Well, headphones can be used similarly.

Headphones by nature can highlight different characteristics in sound to studio monitors in a room. Monitors in a room, how they are positioned in the room will have a direct effect on how you hear sound. Then we also have to consider the acoustics of the room, Is the room acoustically treated and producing a flat response, do you have lots of hard reflective surfaces contributing to the sound, standing wave build-up from low frequencies, and phasing issues? Having a good pair of headphones will eliminate a high proportion of these issues by simply placing them on your head.

Another reason for headphones is home studio use, reducing noise levels at night or at inconvenient times.


Opening of the box and build quality of the – Reference S4x headphones.

Opening the box of the – S4X is an experience in itself. The packing and placement of the contents feel like you are opening a box for an expensive item like a high-quality watch. It’s different compared to other audio companies packaging and feels like there’s a personal touch applied.

The headphones themselves have a nice weight, nicely designed with a metal type grid on the outside of the cans and outer wooden material. The headphone ear cushions are quite deep with leatherette covered padding and feel flexible. The outer frame is a metal design with a softer springy band that adjusts to your head.

The audio cables are detectable and replaceable which is what you want from a set of pro headphones – the cable quality is good with a cord-type material covering a stereo jack lead that splits into a separate – left and right lead – Y splitter. The cable length is approximately 80 inches, which is a good length compared to other headphones in the same field.

Additionally, the headphones come with their own carry bag and a nicely constructed multilingual manual.


How do they sound?

It’s important to understand that when you purchase a pair of high-quality headphones or studio monitors alike, that the focus is not to colour the sound and add extra ear candy tonal qualities.

The aim is to produce an accurate and flat response, and that the S4X do very well

I tested the S4X whilst listening to some heavily compressed mastered tracks, to lighter mastered, pre-master productions, and then live in audio mix projects. My first impressions were, the detail and clarity I could hear was exceptional, stereo width and I could easily hear any low- or high-end distortion. I love that the S4X are very capable of handling low signals as well as louder.

One of my pet hates with some higher-end studio headphones is, they are great at a lower volume but sometimes you like to crank it up a bit to get more impact. Comparatively to other headphone models within the same price range, cranking it up leads to distortion and clipping in the cans, but the S4X handle this very well.

The transparency of the S4X are very honest, particularly when focusing on the lower-end frequencies. I feel they highlight what could be lacking in an audio mix – whilst the mid-range and high end is also transparent, I think the transparency in the lows are unique to the S4X compared to other studio-specific headphones I’ve used. Listening over longer periods didn’t produce ear fatigue. This can often be the case from exaggerated mid-range on other headphones and studio monitors.

Overall, it didn’t take much adjusting to the sound of the S4X and became more enjoyable as a listening and working experience!

Power to the eardrums

As touched on briefly, the S4X headphones are more versatile than just pro audio use. One of the reasons behind this is they don’t require a dedicated headphone amp to drive the cans. Many other studio-based headphones require a higher impedance rating – if you don’t understand impedance, don’t worry just think of it as the amount of power required to fuel the headphones.

“As mixing takes place in many different setups we went with 32-ohm impedance and made them compatible with pro-level and laptop integrated amplifiers. Industry-standard jack connectors make them a plug and play on just about any audio gear.”

Again, this is a big plus for S4X, using the headphones outside of a studio environment, mobile devices, laptops, or other means your ears are adjusting to the transparency of these headphones whilst listening to your favourite music on the go. This also aids a further reference when in the studio.

Pricing and purchase options

The S4X are currently retailing directly on the OLLO audio website at – €399 = approximately £340 or $467.

The pricing is appropriate and comparable with other known branded headphones in this range (slightly lower in price). OLLO audio also has an option to spread your payments over 12 months – with a 30-day trial period included and a 5-year warranty. Delivery from OLLO direct is very quick and tracked.

Further purchase options are currently available at Amazon and specialist retailers.
Full UK distribution (available soon) and further products soon via –

Summing up

Comparatively, in this price range – there are several other known branded headphones manufacturers to choose from. Some offer similar audio transparency and built quality. However, I feel the S4X will make my other studio headphones redundant. Again, the low impedance rating also makes the s4X a winner in comparison. No Headphone amp is required and more versatile.

Other specs – including the frequency response are comparable to other headphones and in many cases – better (check the tech specs). I’m looking forward to producing better audio mixes using the S4X as well as a better transparent listening experience.


Big win for OLLO Audio!


Writer – Blue Amazon requires little introduction whilst mustering many accolades in music production that dates back to the early ’90s to the present day. Blue Amazon releases have included the Interpretations albums series with Zak Gee, singles on Jackpot records, Sony entertainment, Radiate, A Rec, Pro B Tech, etc. Remixes for – Lonya’s – Asymmetric label, Sasha, Skunk Anansie, New Order, Placebo through to artists as Madonna. The progressive club classic – No Other Love, The Javelin album, Underground club collaborations with Alex Flatner and Robert Owens on Kling Klong Records, tracks with Disscut from Germany, Louie Le Fink, and more)

Editor – Mike Mannix


OLLO Audio:

Nova Distribution:

Blue Amazon production:
Blue Amazon artist: