Review: Ollo Audio S5X Immersive Headphones

If You Want To Hear Everything: Ollo Audio’s S5X Immersive Headphones
by Jamie Gillies

Over time with this hobby and as I have progressed with more critical listening, I have found myself listening to more music through headphones. I grew up with headphone and earbud listening, from my first Discman through the iPod era. I then committed to 2 channel audio and speaker listening and put away my cans for a long time.

But as DACs and headphone amps have improved and the space and time needed for critical listening changes, I have turned back to a fair bit of listening through headphones. One caveat before reading this review: I am by no means a headphone obsessive. I do not have five different sets of cans and do not constantly compare brands. So this review is probably more for those of us who want a decent pair of headphones to augment our audiophile system. I also do not have a dedicated headphone amplifier. I have various preamplifiers, DACs and transports with headphone jacks, and some have a bit more preamplification to handle dynamic headphones. But tough to drive headphones, that require specialized power, I simply have no experience with listening. That said, I have listened to headphones by Sennheiser, Focal, HiFiMan, Sony and even Bose. They all have a purpose and they all have different strengths.

Ollo Audio is a Slovenian headphone company that makes dynamic headphones that aim for a flat frequency ideal for studio mixing and mastering. They are not an audiophile headphone company. So comparing these S5X immersive headphones to, for example, Focal Utopias or Stellias, or to Sennheiser HD800Ss or HD820s, is a bit like comparing apples to oranges. Add to this: I don’t have a studio so my headphone gearhead knowledge is limited to audiophile listening.

Unboxing and Trial and Error

Ollo Audio describes the S5X Version 1.0 as reference class, open back, dynamic headphones with flat frequency response for binaural/immersive mixing. The speakers are hand picked, left/right matched transducers that deliver “accuracy and instrument separation.” The artificial leather ear pads and wood outer core of the phone are well designed with an artificial leather strap headband. It also comes with a well made cable although some headphone enthusiasts may want to add their own after market cable preferences.

Oliver Fragman, the proprietor of Le Studio du Son in Montreal, Québec, and the official reseller of Ollo Audio headphones in Canada, kindly sent me these S5Xs with about 60 hours of break-in on them. Eager to try these with the various components I have on hand, I started with my Oppo BDP-105 universal player. The Oppo has a headphone amplifier within the unit and I was curious to see how a neutral flat response headphone would sound or if it could drive it decently enough to achieve a good sound from the cans. It became apparent that this sounded disappointing. The Oppo is a notably bright, somewhat imprecise, jack of all trades unit. The sound of some albums, even those I know well and love, sounded almost too resolving: etched, slightly harsh with a thin top end. Not what I was expecting. I then listened to the Oppo through my noise cancelling Bose Quiet Comfort 15s that I use on airplanes or at the office to listen to podcasts. These were a lot smoother but also had much less definition: you know the old adage, no highs, no lows, must be Bose! The Bose are also effortless to drive so maybe these Ollo cans needed a little more oomph to push them. Just as a comparison, I also have a pair of Sony MDR-7502s. These are typical audio ‘phones common on film sets, in home music producing etc. Nothing special with a clear midrange. They sounded more like the Ollos through the Oppo. My consensus: the Oppo 105 has a pretty weak headphone sound and maybe not the best place to try out these kind of dynamic headphones.

Next I tried the headphone input on my exaSound e62 DAC. This sounded better: streaming files sounded clean, clear but also a little uninvolving: a more ‘what you see is what you get’ sound. This tracks more with what the Ollo S5X promise: a neutral, flat response. Again, the exaSound is not designed for primary headphone listening either. What I did like was the instrument separation and the way vocals sounded. The headphone resolved even difficult recordings. But I had tried this DAC with Sennheisers and Focals and I think most audiophiles would prefer those other headphones in terms of an in-house sound added to the equation while listening through something like a fairly neutral resolving DAC.

Preamplifier Listening

Finally, I thought that maybe the Ollos strengths lie in something designed, at least in part, for headphones. I tried them with two amplifiers: my more contemporary NAD C165BEE preamplifier and my vintage 1977 Marantz 2235B receiver. With the NAD, my overperforming and relatively inexpensive preamp, I really started to enjoy the Ollos. The NAD tends to be less analytical than other preamps. It is not that resolving and not as detailed. This has pluses and minuses: new low dynamic range music sounds good at reasonable volumes but audiophile vocals tend to sound not so great at critical listening levels. The Ollos surprised me: the S5X paired well here. I got a complete picture of the sound especially streaming music from my DAC to the preamp. I started to shut my eyes a lot and just listen. The binaural immersive sound designed for mixing and mastering may take a little bit of getting used to but I started to hear things I had not noticed before. Subtle things, an underlying bass line, background vocals separated from the singer on choruses, drum crash decay as a solo comes to an end. Even on recordings I would not expect to be particularly well recorded or with what audiophiles would say have crushed dynamics, the Ollo S5X was able to present a pretty good soundstage from a headphone jack on a mid-priced preamp.

I tried the S5Xs on the NAD preamp for a solid week: just playing any genre of music: orchestral, film scores, old jazz, new jazz, and a lot of modern music streamed from Tidal Masters. What the S5Xs demonstrated was that some music that sounded really great through headphones actually lost something through my speakers. The headphone listening gave me a feeling, much like I had with Discmans and iPods: it was nice to hear music living in my head again.

And then it dawned on me: the Ollos would be perfect for a dedicated headphone setup with a warmer, or more musical, or tube-like presentation.

So I built one in my home office. I brought my Marantz 2235B up from the analogue vinyl space in the basement, along with my exaSound e62 DAC and Sigma streamer, my Oppo 105, and my Thorens TD-145 turntable. Speakers were left out of the equation and I hooked this up, isolating the turntable and placing it all on my home office desk looking out over the Appalachian foothills of New Brunswick.

Bingo! That slightly warmer but more musical Marantz sound was an ideal match for the neutral, flat response of the Ollos. Vinyl sounded great, streaming sounded great, CDs sounded great. This brought me more of the immersive audiophile sound I was hoping for from the S5Xs. The big difference appears to be air: these headphones were allowed to breathe with the Marantz and that air, especially on the highs, was finally there. This was similar to what we hear when we listen to digital versus wax: the upper mids/highs warmth and air to the follow through on vinyl, versus digital glare and sharp highs on some digital. This was especially the case while listening to CDs.

For a point of reference, I went with an old headphone standby: Bruce Springsteen’s Greatest Hits CD from 1995. I must have listened to this Bob Ludwig mastered album a thousand times since the day it was released, and probably 800 spins were on a Panasonic portable CD player in the late 1990s. I know every single nuance of this greatest hits collection like it’s the soundtrack of my life. I even memorized most of the liner notes. I dialed in that sound in my head from the 1990s on the Marantz, with the treble and bass turned down to accentuate the mids like a Discman, and then I let the music breathe: turned the Hi Filter off and set the tone controls to the 12 o’clock position except for boosting the mids by one notch. Best I had ever heard this album, like I could feel Bruce in the studio, with air around the instruments and his voice especially on The River, My Hometown and Streets of Philadelphia. It allowed me to get deeper into the music: I could really hear the stylistic shifts in production from album to album and decade to decade on a greatest hits compilation that I have always thought of as very well mastered.

I then tried the original CD pressing of Phil Collins’s debut solo album Face Value. Blown away: the dynamics of In The Air Tonight leading to one of the great drum solos of all time were perfect. I was kind of shocked that a little silver disc could sound this big through headphones.

I shifted to my extensive collection of SACDs and tried Diana Krall’s The Look of Love. Cry Me A River sounded like I was monitoring the playback in the studio.

Streaming was also just as enjoyable through the Marantz and the Ollo S5Xs. I then switched to listening to vinyl. I put on Rickie Lee Jones’ self-titled debut. Smooth, warm, huge soundstage through the headphones especially on Chuck E.’s In Love.

Then I tried some 70s AM gold: The Sanford-Townsend Band’s Smoke From A Distant Fire. That inviting Muscle Shoals sound was all over that record and it has this fantastic mix of SoCal studio magic and yacht rock production.

Finally, I tried Tracy Chapman’s self-titled debut. My reaction: unfatiguing, immersive, emotionally connected to the music. What more could you ask for with headphone listening.


Comparison: Ollo S5X vs. Focal Stellia

Satisfied that the Ollos would work in an audiophile setup, I then had an opportunity to do a head to head comparison between the Ollos, at $699 Canadian, versus the Focal Stellia headphones, at $3,999 Canadian. One is open back, one is closed back. One is designed for mixing and mastering, one for the audiophile market, and one is nearly six times the price of the other. I compared these on my friend’s Topping S90 and A90 DAC and headphone amplifier. We ran high resolution files from his network and switched between the two headphones. The Topping gear sounded extremely neutral so we were listening for the differences in the headphones. The Ollos were flat, again, what you likely hear in the studio is what you get. They were detailed and had a nice mix and separation to instruments and vocals. The Focals coloured the sound in particular ways: more bass and a more rolled off, some might say refined, high end. In that setup, the Ollos likely were too revealing and too neutral.

Conclusion and Recommendation

The Ollo S5X immersive headphones would be great in a studio space to give the listener an immersive mixing or mastering experience. People with home studios and those making their own recordings could spend a lot more and get a lot less. But for audiophiles, partnering equipment will be crucial – especially in a revealing, resolving, neutral system. In some cases these headphones could accentuate the “warts and all” presentation of many recordings, which (especially with headphones) can be fatiguing after long periods of listening.

But for people like me, with an imperfect system, one where there is a mix of detail, clarity and warmth, where I am right up against it in terms of detail and depth and dialing in the music is a constant evolution, these headphones work. This is especially true if you have the ability to listen to these headphones either through a warmer, more musical and less analytical preamp or through a tube amplifier or a headphone amplifier that colours the sound to your liking. Then the Ollo S5X headphones are some of the best cans I have ever heard. To compare in Canadian dollars, Focal Stellias are $3,999, Focal Utopias are $5,699, a pair of Sennheiser HD 800S are $1,999, and Sennheiser HD 820s are $2,599. The Ollo S5X headphones retail for just $699 from Le Studio du Son in Montreal.

Last but not least, I want to thank Oliver Fragman for all of his help and advice. Contact Oliver at Le Studio du Son in Montreal.



Frequency response

15 Hz – 22 kHz sweep 1/3 oct p-p range (+/-1) 14.5 dBSPL
20 Hz – 20 kHz sweep 1/3 oct p-p range (+/-1) 12 dBSPL


@ 0 dBu RMS 1 kHz produces (+/-1) 108 dBSPL
@ -23 dBu RMS 0.5-2kHz pink produces (+/-1) 85 dBSPL


+/- 5% 50 Ohm, outboard audio interface recommended

Ear cups dimensions

Outer diameter: 95 mm

Ear cups material

American walnut


Stainless steel and artificial leather
Clamping pressure N/cm² @14.3cm breadth ~0.127 N/cm²

Earpads size

Outer diameter: 95 mm
Inner diameter: 57.5mm
Depth: 20mm

Earpads material

Acoustic foam, extra elasticity poly leather and velour

Cable termination

Detachable 2 meters long Y 2.5mm mini jack


3.5mm jack with an adapter to 6.3mm jack



Magnet type


Transducer type



2 layered

Membrane material

PET 25u

Matched speakers

Handpicked pairs


5-year limited warranty

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About Jamie Gillies (10 Articles)
Biography: I have been an audiophile as long as I have listened to music and was fortunate to grow up with both an analogue Sony hi-fi system and a digital stereo system in my bedroom. I really developed my interest in sound when we bought our first house and I created a dedicated sound room and finally purchased a good pair of speakers. I am also a Professor of Communications and Public Policy and have a research interest in mastering engineers, having had an opportunity to interview and see a number of these legends in their own studios. My musical tastes have evolved as my gear has become more refined and today I listen to well recorded rock and jazz, lots of audiophile recordings and continue my fondness for the SACD format. Besides a deep love of Bruce Springsteen, Bob Dylan and Mark Knopfler, I listen to a lot of jazz, in particular Miles, Bill Evans, Brad Mehldau and Joshua Redman. But my kid keeps me grounded in good modern music as well, especially Taylor Swift and Haim. I also stream a lot of high resolution files and still spin the silver discs. I have a nicely curated selection of LPs and my Thorens turntable gets a workout every week as well. I am currently fascinated with upgrading my nice laid back mid-fi system and am always looking at new equipment and tweaks as I search for that perfect sound.

1 Comment on Review: Ollo Audio S5X Immersive Headphones

  1. Mark from HigherHz sent me a note to say that they’ve posted a video review of the S5X. This is the link:


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