EOFY Sale Now On! Business Finance via Procuret

EOFY Sale Now On! Business Finance via Procuret

Request a Quote


Add your deal, information or promotional text

Sold out

OLLO Audio S4X 1.1 Studio Reference Headphones

Notify me when this product is available:

Studio reference class, open back, dynamic headphones with flat frequency response made in the EU.

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.

We don't pretend to know flat better

Lab research showed massive inconsistencies in popular target curves. So we relied on renowned industry professionals instead and reverse-engineered their preferred EQ compensations as a base for the S4X's frequency response. S4X's sound signature was advised by the pros, not lab geeks. Intrigued? We offer 30 days trial on all purchases.

Amplifier independent

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.

Benefits of individually measured pairs

With your headphones' measurements charts you will have a better understanding of what you're hearing and have an edge in mixing and mastering for best translation of your projects.


Technical Specifications

  • Hand picked and left / right matched transducers delivering accuracy and instrument separation. (+/-1dB SPL tolerance, pink noise, range 100Hz-10kHz in free field) 
  • 50 mm, PET 25u membrane, 2 layered coil, 32 ohms,
  • Dynamic Neodymium speaker with 109dBSPL (S4X) / 111dBSPL (S4R) 1Vrms@1KHz 30ohm output that makes them work with smart devices too.
  • Replaceable using home tools.


  • Replaceable earpads with outer diameter of 90 mm(3.5inch), inner diameter of 55mm(2.2inch) and depth of 20mm(0.8inch).
  • Hybrid artificial leather and velour earpads to control flow resistance around the earpads seal resulting in smoother response in low mids and mids (150Hz-1kHz) perceived as natural timbre on vocals, pianos, strings,...
  • 1kHz @ 85dBSPL sweep THD < 0.084%S4X / 0.079%S4R , Variation in frequency response in band from 20Hz to 20kHz ~13,7 dB SPL S4X / 10,0dB SPL S4R, pink noise IEC 60318-1 compatible standard.
  • Fully separated front and back of the speaker for minimal phase cancellation and more direct sound signature. SoundSeal™ 


  • Self-adjusting artificial leather strap
  • Clamping force set for most neutral frequency response on industry standard bitragional diameter of 14.3cm (KEMAR)
  • Stainless spring steel powder coated
  • 360 earcups rotation
  • Strap and steel are replaceable using home tools


  • Detachable braided silicone cable employing OFC core to ensure minimal signal distortion.
  • Color labeled L and R (Left is Black)
  • Reversible to have cable coming down behind your back when playing an instrument or in front when producing with a desktop interface.


  • 5 years limited warranty (Earpads and cable are excluded due to the nature of exposure)

Customer Reviews

Be the first to write a review