
S4X 1.2 REFERENCE
Flat out of the box...
...is the phrase reviewers coined for the S4X. Their neutral and honest sound signature was perfected in close R&D collaboration with professional mixing and mastering engineers.
S4R 1.2 RECORDING
Hear your performance as it is, no sugar coating
Your recording headphones are the first touch with your performance. All the details must be preserved and nothing should be exaggerated. A well tuned recording headphones will have no mercy on you and push you to your absolute best.

IEC 60318-1&4 ear simulator
HOW DO THEY SOUND?
We measured the frequency responses of the main mixing headphones on the market, so you can get a visual representation and compare. (DT series, HD series, Focal, Audeze etc)
Available in the UK at
HANDPICKED COMPONENTS
MATCHED SPEAKERS
We measure all speakers in every series and match them together to achieve minimal possible tolerance between left and right channel.
• Neodymium
• 2 layered coil
• PET membrane 25u


POWERED by SAATI
HIGH PRECISION WOVEN MESH
Designed and manufactured to improve acoustics and protect sensitive components.
• Smooth monofilament fiber
• Efficient protection from dust, metal particles and liquids
• Strict airflow control
CUSTOM DESIGNED
EARPADS
They fit around your ears snugly but provide enough padding to rest comfortably against your head.
• Outer diameter: 90 mm
• Inner diameter: 55mm
• Hybrid nautical leather and velvet
• Soft memory foam


DETACHABLE
2000 MM CABLE
You can easily exchange a cable with a new one in case it breaks or even buy some other cable design if you prefer. Just unplug and replace.
• dual 2.5mm TRS and 3.5mm TRS
• 6.3mm adapter
• connector: 3.5mm jack with an adapter to 6.3mm jack
TECHNICAL SPECIFICATIONS
Frequency response |
Variation in frequency response in band from 20Hz to 20kHz ~13,7dB (s4x) ~10,0dB (s4r) SPL *IEC60318-1 |
SPL/sensitivity |
108dB s4x 111dB s4r / 1vrms@1Khz 30ohm |
Impedance |
32ohm, smart devices ready |
Ear cups dimensions |
Outer diameter: 90 mm |
Ear cups material |
American walnut |
Headband material |
Stainless steel and nautical artificial leather |
Earpads size |
Outer diameter: 90 mm Inner diameter: 55mm Depth: 20mm |
Earpads material |
Acoustic foam, extra elasticity poly leather and velour |
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 25u |
Matched speakers |
Handpicked pairs |
Warranty |
5-year limited warranty |
Trial period |
30 days from delivery date |
More technical data:

NATURAL FEEL
PREMIUM MATERIALS
Timelessness of stainless steel coupled with luxury nautical leather and velour for maximum comfort. Paired with a smell of a fresh sustainably sourced wood.
AWARDED BY EXPERTS
GERMAN DESIGN AWARD winner
The German Design Award is the international leading prize of the German Design Council. Their goal is to discover, showcase and recognize unique design trends.
We are proud to be declared a winner in the electronics category.


NATURAL COMFORT
EAR FATIGUE NO MORE
Custom designed velour earpads fit around your ears snugly while the self-adjusting strap provides for a perfect fit. Combined with a balanced sound, it will enable you to work on headphones for hours.
QUALITY CONTROL
WE MEASURE EVERY PAIR
OLLO headphones are individually tested and measured and come with the frequency response measurements chart in the package.


WE'VE GOT YOUR BACK
5 YEARS LIMITED WARRANTY
We trust our products and we build them to last. Our 5 year warranty program is a testament to our commitment to quality.
"I love my S4X reference headphones: they sound fantastic, are reliable and trustworthy, sit comfortably on my head and around my ears, don't give me ear-fatigue and don't press my ear onto the glasses allowing for continued and comfortable use.”
- MARC URSELLI
[U2, Foo Fighters, Nick Cave, Lou Reed, Sting, Keith Richards]
"The separation between the instruments, the dynamic and stereo image is perfect to be comfortable to mix with them.
I was amazed by the S4. But I am floored by the S4X!
Truly amazing."
- WILLIAM ROBERTSON
[Mick Jagger, Nicki Minaj, Will.I.Am]

TRY BEFORE YOU DECIDE
You have 30 days to try it, use it, and love it — if you don’t fall in love by that time, reach out to our team to initiate an easy return and refund process.

5 YEARS LIMITED WARRANTY
We trust our products and we build them to last. Our 5 year warranty program is a testament to our commitment to quality.

HANDBUILT ON THE EDGE OF THE ALPS
OLLO factory is located one hour drive away from Venice Italy.